Can I microwave cooked and peeled prawns?
My best method for reheating frozen prawns is to cover them with hot liquid.  Broth is good, but water works.  I even just use hot tap water.  In a few minutes they are ready to eat.  Even if I am adding them to a dish, I thaw them in warm water and add after I have taken the pot off the flame.  Frozen shrimp just get rubbery too easily.