Heat the avocado oil in a medium pot or large skillet over medium heat. Add the onion, jalapeño, garlic, and salt and cook, stirring occasionally, for 8 minutes, or until softened.

Stir in the taco seasoning and cayenne, if using, and cook for 1 minute. Add the beans and 1/4 cup of the reserved bean liquid and cook for 5 to 8 minutes, or until the vegetables are totally soft and the mixture is thick. If the pan becomes dry, add the remaining 1/4 cup bean liquid.

Mash some of the beans with the back of a wooden spoon to make the mixture lightly creamy. Stir in the lime juice and season to taste.

Assemble tacos in the tortillas with the beans, pickled cabbage, crema, Cotija cheese, jalapeños, and cilantro.