Step 1

Heat the oil in a skillet over medium heat. Add the onion and cook down for a couple minutes. Pour in the beans, taco seasoning and a little bit of water. Cook for 5-7 minutes, or until the beans are heated through and the onion is tender. Gently smash some of the beans before serving - add more water if the beans start to dry out.

Step 2

Meanwhile, add all of the avocado salsa ingredients to a bowl and mix to combine. Taste and adjust the seasonings as needed. Set aside.

Step 3

Add the chipotle mayo ingredients to a bowl and mix to combine. Set aside.

Step 4

To assemble, heat the tostada shells in the oven or air fryer. Layer each tostada shell with beans, cabbage, avocado salsa and chipotle mayo. Sprinkle with more cilantro and serve with lime wedges on the side.