Sorry, I meant to get to this yesterday. See my question on Emacs StackExchange and my configuration file where I added this functionality. Basically, you go to insert a link with C-c C-l, type id: <ENTER> and then you'll be prompted to find the org-id via outline completion. I've reproduced the code below for convenience:

#+BEGIN_SRC emacs-lisp
;; Add ID properties to all headlines in the current file which do not already have one
(defun my/org-add-ids-to-headlines-in-file ()
(interactive)
(org-map-entries 'org-id-get-create))
#+END_SRC

The other responses look good as well. Hope this helps!
-D

On Sat, Aug 1, 2015 at 12:03 PM, John Kitchin <jkitchin@andrew.cmu.edu> wrote:
usually it is pretty easy to add new functions in helm, but it is less
easy in this case because the source is dynamically generated from a
function. So, in this case I think we have to just redefine the function
that generates the source. here is an example that I think makes an id
link as a new action.

#+BEGIN_SRC emacs-lisp
(defun helm-org-insert-id-link-to-heading-at-marker (marker)
  (with-current-buffer (marker-buffer marker)
    (let ((file-name (buffer-file-name))
          (id (save-excursion (goto-char (marker-position marker))
                              (org-id-get-create)
                              (org-id-store-link))))

      (with-helm-current-buffer
        (org-insert-link
         file-name id)))))


(cl-defun helm-source-org-headings-for-files (filenames
                                              &optional (min-depth 1) (max-depth 8))
  (helm-build-sync-source "Org Headings"
    :candidates (helm-org-get-candidates filenames min-depth max-depth)
    :action '(("Go to line" . helm-org-goto-marker)
              ("Refile to this heading" . helm-org-heading-refile)
              ("Insert link to this heading"
               . helm-org-insert-link-to-heading-at-marker)
              ("Insert id link to this heading" .
               helm-org-insert-id-link-to-heading-at-marker))))

#+END_SRC
Xebar Saram writes:

> Hi again
>
> so excited over this had to ask 2 more questions ;-)
>
> 1.can that function include/link to org-id  (so that it can keep the links
> even if the headers move around in/out of the files)
> 2.i saw there are 3 options to that helm function. can this be customized
> to add more commands (can really think of which ones know but could see
> potential in future :))
>
> thx so much John as always you rock ;-)
>
> Z
>
> On Sat, Aug 1, 2015 at 8:36 PM, Xebar Saram <zeltakc@gmail.com> wrote:
>
>> John, this is superb!
>>
>> thx so much it answers all my needs, what a great find :)
>>
>> kind regards
>>
>> Z
>>
>> On Sat, Aug 1, 2015 at 7:33 PM, John Kitchin <jkitchin@andrew.cmu.edu>
>> wrote:
>>
>>> (helm-org-agenda-files-headings) seems to do this already for all
>>> headlines in your agenda files. the third action is to insert a link to
>>> the selected headline.
>>>
>>> You can use let to temporarily define the org-agenda-files list to what
>>> you want, and just use the (helm-org-agenda-files-headings) command for
>>> non-agenda files.
>>>
>>> e.g.
>>>
>>> #+BEGIN_SRC emacs-lisp
>>> (defun insert-heading-link (dir)
>>>   "select a headline from org-files in dir and insert a link to it."
>>>   (interactive  (list (read-directory-name "Directory: ")))
>>>   (let ((org-agenda-files (f-entries
>>>                            dir
>>>                            (lambda (f)
>>>                              (string=
>>>                               "org"
>>>                               (file-name-extension f)))
>>>                            t)))
>>>     (helm-org-agenda-files-headings)))
>>> #+END_SRC
>>>
>>> gives me a helm buffer to select headlines from org-files in the
>>> directory I select and when I press f3 (for the third
>>> action), it inserts a link to the selected headline. It does the file
>>> finding recursively, so you might not want to run this on /  ;)
>>>
>>> You could bind it to a key for easy use.
>>>
>>> Xebar Saram writes:
>>>
>>> > Thx so much Bernhard
>>> >
>>> > this looks really promising. i never had luck with either company or
>>> > auto-complete t o get it to work reliably (it often stops working even
>>> > though its still in the mod bar).
>>> > anyway i tried it and added this to my config (after cloning from git):
>>> >
>>> > (add-to-list 'load-path "/home/zeltak/.emacs.g/company-org-headings")
>>> > (add-hook 'org-mode-hook
>>> >  (lambda () (set (make-local-variable 'company-backends)
>>> >     '((company-org-headings)))))
>>> >
>>> > i dont see it completes on org heading, is there any keys i need to
>>> press
>>> > or anything else in need to config? does this work only when you try to
>>> > insert a link?
>>> >
>>> > best and thx so much, this look awesome
>>> >
>>> > P.S have you considered Helm for this as well?
>>> >
>>> > best
>>> >
>>> > Z
>>> >
>>> >
>>> >
>>> > On Sat, Aug 1, 2015 at 12:07 PM, Bernhard Pröll <bmutbuerger@gmail.com>
>>> > wrote:
>>> >
>>> >> Hi Saram,
>>> >>
>>> >> I've been in the same boat and decided to write a company-backend for
>>> >> this purpose. So if you're already using company-mode, this may be
>>> worth
>>> >> looking into:
>>> >>
>>> >> https://github.com/mutbuerger/company-org-headings
>>> >>
>>> >> Keep in mind that I'm in the process of learning Elisp and
>>> >> there has been little to no testing done on the package. Furthermore it
>>> >> uses org-store-link instead of org-id-store-link.
>>> >>
>>> >> Regards,
>>> >> Bernhard Pröll
>>> >>
>>> >>
>>> >> On Fri, 31. Jul 09:43, Xebar Saram wrote:
>>> >>
>>> >>> i also have a similar workflow and would love to hear Dominic if you
>>> >>> found a
>>> >>> solution for this or if anyone on the list has other suggestions?
>>> >>>
>>> >>> best
>>> >>>
>>> >>> Z
>>> >>>
>>> >>> On Tue, May 12, 2015 at 10:57 PM, Dominic Surano <sk8ingdom@gmail.com
>>> >
>>> >>> wrote:
>>> >>>
>>> >>>    Hello,
>>> >>>
>>> >>>    I use org-mode a lot like a wiki so links to other org-mode
>>> headings
>>> >>> are
>>> >>>    very common. Currently, I navigate to the heading or pull it up in
>>> an
>>> >>>    agenda view, store the link with C-l, going back to where I want to
>>> >>>    insert the link, then insert the link with C-c C-l RET. This is a
>>> bit
>>> >>>    time consuming.
>>> >>>
>>> >>>    Instead, I would prefer to map a key that allows me to insert a
>>> link at
>>> >>>    the current point using tab completion similar to org-refile (C-c
>>> C-w).
>>> >>>    Looking through org-id.el, it seems like
>>> org-id-get-with-outline-path
>>> >>>    completion was designed for this purpose. I tried:
>>> >>>
>>> >>>    (global-set-key "\C-ci" (lambda () (interactive) (org-id-get-with
>>> >>>    outline-path-completion)))
>>> >>>
>>> >>>    but it didn't work as intended. Anyone have any ideas?
>>> >>>
>>> >>>    Thanks!
>>> >>>    -D
>>> >>>
>>> >>>    For reference, I have the following set in my configuration:
>>> >>>
>>> >>>    ;; Use global IDs
>>> >>>    (require 'org-id)
>>> >>>    (setq org-id-link-to-org-use-id t)
>>> >>>
>>> >>>    ;; Update ID file .org-id-locations on startup
>>> >>>    (org-id-update-id-locations)
>>> >>>
>>> >>>    ;; Targets include this file and any file contributing to the
>>> agenda -
>>> >>>    up to 9 levels deep
>>> >>>    (setq org-refile-targets (quote ((nil :maxlevel . 9)
>>> >>>                                     (org-agenda-files :maxlevel .
>>> 9))))
>>> >>>    (setq org-refile-use-outline-path 'file)
>>> >>>    (setq org-outline-path-complete-in-steps t)
>>> >>>    (setq org-refile-allow-creating-parent-nodes t)
>>> >>>
>>> >>>
>>> >>>
>>> >>>
>>> >>>
>>>
>>> --
>>> Professor John Kitchin
>>> Doherty Hall A207F
>>> Department of Chemical Engineering
>>> Carnegie Mellon University
>>> Pittsburgh, PA 15213
>>> 412-268-7803
>>> @johnkitchin
>>> http://kitchingroup.cheme.cmu.edu
>>>
>>
>>

--
Professor John Kitchin
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
@johnkitchin
http://kitchingroup.cheme.cmu.edu



--
Dominic Surano
Email is my fastest and preferred method of contact
Phone, address, etc. available upon request

Life should be an adventure