I make quesadillas in the microwave. You don't need to grate the cheese; slicing is just as good.

This assumes you're using corn tortillas; I assume flour tortillas don't microwave well.

However, I would recommend grating a block for a couple days worth at a time and keeping it in the fridge in a food storage container. That way you don't need 3 shredders or to spend all your time cleaning shredders every time you want a quesadilla. An electric rotary shredder or a kitchen-aide attachment makes it trivial.

Also, try adding a little canned Red Enchilada sauce to your quesadilla or egg and cheese burritos. It's life changing!