You can heat up a tortilla in any number of ways: the microwave, the oven, or pan frying. If you're looking for an easy, mess-free way to do it, cooking blog The Kitchn shows off a simple way to heat up a tortilla right on the burners of a gas stove -- no dishes required.All you need to do is fire up the burners on a gas stove on the lowest setting, place a tortilla directly on the burner, and flip them after about 45 seconds. As you finish cooking the tortillas, throw them onto a towel and close the towel up to steam the tortillas and keep them warm. The process works for both corn and flour tortillas, but don't use oil, because it will smoke up your kitchen. Head over to The Kitchn for a full guide for cooking these up for yourself.
My favourite Way to Heat Up Tortillas [The Kitchn]