Heat oven to 350 degrees F. Heat oil in a large nonstick skillet over medium-high heat. Add beef, onion and green pepper to skillet and cook, stirring occasionally, for 6 minutes. Drain any accumulated fat and stir in cumin; cook 1 minute. Stir in salsa and heat through; remove from heat; set aside.
Coat a 9-inch springform pan with nonstick cooking spray. Place 1 tortilla in the bottom of pan, then top with 1 heaping cup meat mixture, spreading it evenly and leaving a 1-inch border around edges. Sprinkle meat with 1/2 cup cheese and top with 1 tortilla, pressing down gently. Repeat layers 3 more times.
Place springform pan in oven and bake at 350 degrees F for 15 minutes. Let stand 5 minutes before slicing and serving.