In a skillet set over medium heat, add the ground beef. Cook for about 5-7 minutes, using a spatula to break it apart and ensure it cooks evenly until no pink remains.
Once the beef is browned, sprinkle in the taco seasoning. Pour in about 2 tablespoons of water to moisten the mixture. Continue cooking for an additional 2-3 minutes, stirring occasionally, until well combined and uniformly heated. Remove the skillet from the heat and set aside.
Preheat your oven to 375°F (190°C). Arrange the tostada shells on a baking sheet and place them in the preheated oven. Bake for about 5 minutes or until they are perfectly crispy and warm.
To build each tostada, start by spreading a generous layer of refried beans onto the crisp tostada shell. Follow this with a hearty scoop of the seasoned beef mixture, ensuring an even distribution.
Next, pile on the shredded lettuce, diced tomatoes, and the shredded cheddar cheese for a burst of color and flavor.
Top each assembled tostada with a dollop of creamy sour cream and scatter a few sliced black olives over the top for an added savory bite.
Garnish with fresh cilantro sprigs to bring a bright touch, and serve immediately with lime wedges on the side, perfect for squeezing over the tostadas for an extra zing.