Rinse the black beans and place them in a saucepot. Cover generously with water.

Bring to a boil over medium heat, then reduce the heat and simmer, loosely covered, until the beans are tender, about 1 hour. Drain, reserving the water. Set the beans aside.

Toast the avocado leaves and chiles in a skillet or on a griddle over high heat until fragrant, about 30 seconds. Set aside.

Remove the chiles to a bowl of hot water and soak until softened, about 10 minutes. Drain.

Place the beans, avocado leaves, chiles, 2 cloves of garlic, and enough reserved bean cooking water to facilitate blending in a blender. Blend well until pureed, working in batches if necessary.

Heat 1/4 cup of oil in a large skillet over medium heat. Add the chopped onion and 3 cloves of garlic and cook until lightly browned, 3-4 minutes. Discard the onion and garlic.

Add the ground bean mixture and enough water (use the bean cooking water if any remains) to thin to the consistency of an enchilada sauce. Cook until blended and heated through.

Stack the tortillas, wrap them in wax paper or parchment paper, and microwave to soften for 2 minutes.

Heat the remaining 3/4 cup of oil in a skillet to 350 degrees F.

Fold the tortillas in quarters and fry, one at a time, for a few seconds on each side. Do not allow them to become crisp. Drain on paper towels.

To serve, place the folded tortillas, a few at a time, in the bean mixture just until softened. Do not let them soak too long or they will dissolve.

Place the tortillas on a plate, spoon additional sauce over them, and top with the crumbled queso fresco, parsley, and sliced onion.