If you are not technical, then you're not going to be able to judge technical skill. Sorry, but you're not. I could tell you to ask some of the same questions that I would. (eg If you don't know something, how would you find out? Tell me about a recent programming problem that you had and how you resolved it.) Those are good questions, but you would simply not be able to get the same information from their answers that I would.

Therefore if you have anyone technical on board already, have them do a follow-up technical interview. If you don't, it may be worthwhile to hire someone external just to do a technical interview. If that is not feasible, ask for a code sample and have a technical person review it for you and give feedback.

I'm serious. The problem that you're up against is that you can't tell when someone has technical skill. Compounding that problem is that there are lots of non-technical or semi-technical people out there who are good at bafflegab but you don't want. Conversely many technically competent people tend to be introverted and therefore do not present themselves very well even though they might be people that you really want.