Preheat oven to 450 degrees. Spread 1/2 the can of refried beans on one pizza crust. Top with 1/2 cup pizza sauce, followed by 1/2 the meat and 1/2 the cheese. Shake 1 tablespoon taco seasoning over the top and then add your desired amount of onions and bake until the crust is golden brown. Remove from oven and sprinkle 1/2 the shredded lettuce, tomato, and olives over the top. Put some sour cream in a plastic sandwich bag and snip off the corner. Drizzle the sour cream artistically over the top of the pizza. Crush Doritos and add them over the top of the sour cream. Add any additional toppings, slice, and serve. Repeat with all steps to make the second pizza.