Place ground beef in a large, deep skillet. Cook over medium high heat until evenly brown. Drain and stir in taco seasoning mix and water. Mix in the refried beans; set aside.
Spread the beef mixture evenly on two tortillas. Top each tortilla with a second tortilla. Place even amounts of Monterey Jack cheese and Cheddar cheese on top of the second tortillas. Place the tortillas onto a large baking sheet.
Bake in the preheated oven 10 minutes, or until cheeses are melted.
Remove from oven and top with sour cream, tomato, avocado, black olives and green onions. Cut each pizza into 8 wedges and serve warm.