Heat oven to 425°F. Coat large baking sheet with cooking spray.
Coat large nonstick skillet with cooking spray. Heat over medium-high heat. Add steak strips, onion, green pepper and cumin; cook, stirring constantly, 5 to 7 minutes or until meat is browned and vegetables tender-crisp. Stir in salt. Remove from heat.
Sprinkle half the cheese over half of each tortilla. Top with steak mixture. Sprinkle with remaining cheese. Fold tortillas in half to cover filling; fasten each with wooden pick. Place tortillas on prepared sheet.
Bake in 425°F oven for about 8 minutes or until lightly browned.
Meanwhile, coarsely chop tomato. Stir together tomato and salsa in small bowl.
Cut each quesadilla into 3 triangles. Serve with salsa mixture and sour cream if desired. Remove picks before eating.