Personally, when conducting technical interviews, I try to keep the interviewee right at the limits of their knowledge and ability. It's sort of like standing blindfolded in a room and walking in different directions until you hit a wall to get a sense of the size of the room (don't try this at home). So this often involves starting overly complex, then walking back until you find the interviewee's comfort zone. Let them demonstrate their knowledge for a while (and hopefully gain back some confidence), then push them out to the complexity zone again until they stop answering/start looking uncomfortable again.
To give a concrete example of what that would look like with this question (let's call "A" the interviewer and "B" the interviewee):
A: Thanks for coming in today! We here at CompuMegaCorp are glad you decided to interview with us, and personally, I hope you're enjoying the day so far...
B: Uh...yeah (shifts nervously in seat)
A: Great! So, for the projects you'd be working on here, we make heavy use