"Queso" is cheese in Spanish. And a quesadilla is a toasted tortilla with melted cheese inside. But in addition to cheese, you can put practically anything in a quesadilla.
1) Wheat Tortillas - 4
2) olives - few
3) salad leaves(lettuce)
4) coriander leaves - few(chopped)
5) capsicum, peas, corn, mushrooms,tomato, grated carrot,onion (any of your fav veggies which does not require heavy cooking)
8)Swiss cheese or mozzarella cheese - 1 cup(grated)
1) Basically you get different kinds of Tortillas. Any kind will do. They are nothing but just flat rotis.
2) Take 1 tortilla, toast it with cheese on it, until the cheese melts and covers the tortilla. (add some salt if you need). Add finely chopped veggies, coriander leaves, olives, salad leaves on the cheese melt. And another layer of cheese on top of veggies.
3)Lay another toasted tortilla on top of this tortilla and press it together.
4) It will be like a tortilla sandwich. You can cut it into 1/8 pieces, so each tortilla sandwich has 8 pieces.
It is a quick snack and is very tasty.
Here is another view..