PREHEAT the oven to 350° F. Spray 13 x 9-inch baking dish with nonstick cooking spray.
SPRAY large, nonstick skillet with nonstick cooking spray. Add peppers, onions and cumin; cook over medium-high heat, stirring occasionally, for 6 to 8 minutes until vegetables are tender.
MEANWHILE, COMBINE 1 1/4 cups evaporated milk, cheese and chilies in small saucepan. Cook over medium-low heat, stirring constantly, until cheese has melted and mixture is smooth. Remove from heat. Stir 3/4 cup of cheese sauce into heated brown rice; reserve remaining cheese sauce.
COMBINE refried beans and remaining 1/4 cup evaporated milk in medium, microwave-safe bowl. Microwave, uncovered, on HIGH (100% power) for 3 to 4 minutes, stirring after each minute or until slightly thickened.
FILL tortillas with hot beans, rice and vegetables, dividing equally. Fold sides over filling. Place filled burritos, seam-side down, in prepared baking dish. Top with remaining cheese sauce. Cover with foil.
BAKE for 20 to 25 minutes or until heated through. Serve with salsa and guacamole, if desired.
• Cooked chicken or ground beef may be added to filling.
• Look for precooked ready-to-use brown rice to save prep time.