Heavily grease an 8x8" casserole dish. Set aside.
Heat olive oil in skillet over medium heat.
Brown ground beef with onion over medium heat until no longer pink.
Drain grease.
Add water and taco seasoning and cook until sauce thickens.
Preheat oven to 350.
Spread beans in a layer in bottom of prepared casserole dish.
Top beans with the ground beef mixture.
Then top with a layer of salsa.
Top with 1/2 cup of each of the shredded cheeses and bake for 15 minutes until cheese is melted.
Top with Fritos, lettuce, tomatoes, olives, green onions and remaining cheeses.