Wash hands with warm, soapy water for 20 seconds.
Spray a pan with cooking oil.
Chop vegetables. Cook on medium heat for 4-5 minutes, stirring frequently. Remove from pan.
Spray pan with cooking spray. Place one tortilla in the pan. Sprinkle with half the vegetables and half of the cheese.
Place a second tortilla on top. Cook on medium heat for 4-6 minutes or until the cheese starts to melt and the bottom tortilla starts to brown.
Flip quesadilla. Cook for 4 minutes or until tortilla browns.
Repeat steps 4-6 for the other two tortillas.
Cut each quesadilla in half. Serve with salsa.