Crumple 4 large sheets of foil to make 4 (3-inch) balls; place on baking sheet. Top each with 1 tortilla; spray with cooking spray.
Bake 6 to 8 min. or until tortillas are golden brown. (Tortillas will drape over balls as they bake.)
Meanwhile, brown meat with chili powder in large nonstick skillet. Stir in beans and salsa; cook 5 min. or until heated through, stirring occasionally.
Fill tortilla shells with salad greens, meat mixture, cheese and tomatoes.