1/2 lb. roast beef, thinly sliced
1 small onion, thinly sliced
1/4 cup diced green bell pepper
1/2 cup medium salsa, divided
1 cup shredded cheese (eg. pizza blend)
4 flour tortillas (7\" size)

Microwave sliced onion and diced green pepper for 3-4 minutes in a microwavable bowl.  Stir in 3 Tbsp. salsa. 

Sprinkle 1/4 cup shredded cheese over each tortilla, place beef slices on top of cheese, then salsa mixture, dividing up evenly.  Fold tortillas in half.

Heat quesadillas for about 2 minutes each side on a preheated skillet, until cheese is melted and beef is hot.  Serve quesadillas with remaining salsa, either on top or beside.