Hi Chaim,
If you're looking for Agile Platform Developers you may hire them based on their level of certification, that would mean posting a job looking for OutSystems Associate, Professional or Expert Developer.
On the other hand, Evert is right, training people in OutSystems is far more simple than training them for Java, Ruby or C#. If that's your case, the people you're looking should have:
Their proficiency with SQL or with any other programming language will influence their learning curve.
Cheers,
Mário