On occasion there will be an ad for editors, but what I really would suggest as your best route is think about the companies you like most to work with and who consistently give you great scores, especially on narrative rich shops (which tells you they recognize that you 'get it'). Check the websites to see if there is a 'careers' tab to contact them or go through your scheduler or if there is an owner email, contact them. Give them your shopper identification so they can easily look up your work through their system and make your case.
That being said, I'm not convinced you could make much of a living at it.