I apologize if this has been asked and answered before. If Maarek got 2 crits in a single attack do I deal and look at 3 cards picking 1 to resolve for each crit?

Yes you resolve the crits one at a time drawing 3 cards for each crit dealt.

Team him up with an Advanced Targeting Computer and let the good times roll.

Assuming booth [kaboom] results will be resolving without Shield tokens to remove you will look at three cards to choose which one your opponent draws for each result. Note that any results not selected from the first [kaboom] will be discard and most likely unavailable to be drawn with the second [kaboom].

Yes, you 3 different cards are drawn for each [kaboom] that Maarek resolves against an opponent.

Note that if that opponent is Leebo then Leebo will get to draw an additional card and select which one to keep. Maarek picks up three and selects one to give to Leebo who then picks up another and decides which one to keep; if Leebo had Determination you can probably guess which cards will be 'kept' just so they can immediately be discarded.