Mash beans with salsa. Spoon bean mixture down center of each tortilla, dividing evenly. Cut half of cheese into 8 sticks. Place one stick over beans on each tortilla. Roll tortilla to enclose. Place seam-side down in greased shallow baking dish. Pour enchilada sauce over all. Grate remaining cheese and sprinkle over sauce. Bake in preheated oven, 350 degrees F. for 16 minutes. Top with lettuce and sour cream.