Prep and place tostada toppings (lettuce, cheese, tomatoes, etc.) in small bowls; place them on the counter. *If getting toppings ready early in the day, cover and refrigerate until ready to use.

Combine refried beans and water in a small saucepan. Stir and cook on low heat until heated through. Keep beans warm while you prepare tortillas.

Pour oil ½" deep in a medium skillet. Heat on Medium until very hot, but not smoking. A drop of water should sizzle when added. Carefully place a tortilla in the hot oil. The oil should instantly sizzle around the edges. Cook for 30 seconds, then turn tortilla to the other side using tongs. Continue to cook until tortilla is very crisp on both sides. Use tongs to press the tortilla down (in the center) in the oil, so the middle of the tortilla is very crisp to hold the weight of the toppings. Turn tortilla over again (if necessary) to ensure crispness on all sides.

Transfer tortilla to several layers of paper towels, which will absorb excess oil as it drains. Repeat with remaining tortillas, until all are cooked, and well-drained.

Spoon 2 big Tablespoons of hot refried beans on each tortilla (there'll be beans leftover). Gently use the back of a spoon to spread beans over the tortilla without cracking it.

Add shredded lettuce on top of the beans, then grated cheese and diced tomatoes, dividing evenly between tostadas. Garnish with taco sauce, salsa, sour cream, cilantro and/or olives, if desired. Serve and enjoy!