Heat oven to 375 degrees F. Coat 9-inch pie plate with cooking spray. Brush sides of tortillas lightly with oil; cut in half.
Sauté onion and pepper in remaining oil in nonstick skillet 7 minutes, until slightly softened. Stir in chili powder, cumin, salt, garlic; cook 5 minutes, until vegetables are tender. Stir in salsa, beans and beef.
Spoon mixture in center of pie plate. Tuck tortilla halves around rim. Spread meat mixture level. Stir together sour cream and milk; spoon on top. Sprinkle with cheese.
Bake in 375 degree F oven for 20 minutes or until heated through. Makes 4 servings.