Preheat oven to 400°F. Spray a large baking sheet with cooking spray.
In a skillet over medium heat, brown the ground beef. Drain excess fat.
Add taco seasoning and water. Simmer for 5 minutes until thickened.
Warm refried beans in a small pot or microwave until spreadable.
Place 4 tortillas on the prepared baking sheet. Spread each with a layer of beans, then a layer of seasoned beef.
Top with another tortilla, then spread a spoonful of enchilada or taco sauce on top. Sprinkle generously with cheese.
Bake for 10-12 minutes or until cheese is melted and bubbly.
Remove from oven and top with diced tomatoes, black olives, and green onions.
Cut into quarters and serve hot.