2 flour tortillas (okay, this is going to sound disgusting, but if you can find them, get the kind made with lard rather than shortening--they are soooo much better tasting and authentic)
Couple fistfuls (about 1/2 cup, maybe) of shredded mexican cheese (monterey jack works well, or cheddar--they have these bags of shredded mexican blend in the dairy section that will work just fine)
Two tablespoons of salsa (the hotter the better)
Little bit of garlic powder
As far as hardware goes, you'll need:
A griddle or big skillet
A butter knife
Maybe a cheese grater, if you don't get the pre-shredded cheese
Lay out your two tortillas and butter one side of each. Then flip them over, butter side down.
Spread the shredded cheese over one of the tortillas until it's about a quarter inch thick all around.
Spoon some salsa on the top of the cheese.
Sprinkle with a little garlic powder.
Put tortilla number two on top with the butter side out (so now you've got cheese and salsa sandwiched between two tortillas, with butter on the top and bottom of the sandwich).
Stick the quesadilla on the griddle and turn the burner up to medium. Once it starts cooking, use the spatula to lift up the bottom tortilla so you can check its color. When it's golden brown, flip the quesadilla over. Then cook it until the bottom side is golden brown too. The cheese will melt and mix with the salsa.
And boom, you have yourself a quesadilla.
Variation: Las quesadillas locas con el pollo que es el mas maravilloso del mundo
To mix it up a little, you can add chicken to your quesadillas. Take a skinless boneless breast and stick it on a George Foreman grill for about nine minutes. Then slice it into strips. Put the chicken strips on the quesadilla right after the salsa and then follow the rest of the directions the same way.