If you're in a situation where the best way you have to assess a candidate is to ask them questions, I'd recommend focusing on types of questions that open up r

If you're in a situation where the best way you have to assess a candidate is to ask them questions, I'd recommend focusing on types of questions that open up room for discussion about how the candidate thinks and works rather than simply asking trivia questions about Apple's frameworks. In context of iOS/Obj-C/Cocoa, ask about MVC. Ask about delegates versus blocks versus notifications as mechanisms of communicating between objects. Ask about CocoaPods, but framed as a larger question of when and how to bring in and manage third-party dependencies versus building them yourself. Give them the opportunity to share how they think, not just what they know.