Re: Past simple or present perfect
In the right context, we can.
A. I've met Tom Cruise.
A. Yes, really. He was very nice.
B. I don't believe you.
A. Well, it's true. I have met him!
B. Oh, come on! When have you met Tom Cruise?! (The word "you" would probably be very heavily stressed and the tone of voice would be incredulous.)
A. Last year, in the lobby of a hotel in L.A.
I agree that "When did you meet him?" would sound better as a standard question but there is something in the intonation of disbelief or surprise that leans me towards "... have you ...?"
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.