Preheat the oven to 425 degrees F. Line a sheet pan with parchment paper.
In a large bowl, stir the black beans, red onions and jalapeños with 2 tablespoons olive oil, cumin, garlic powder, paprika, oregano, 1 teaspoon kosher salt and 1/2 teaspoon black pepper. Once they are coated in the spiced-oil mixture, smash the beans with a fork.
To warm the tortillas, wrap them in a damp paper towel. Microwave for 30 seconds. This steams the tortillas, so then you can fold them to assemble the tacos.
Brush each tortilla with olive oil on both sides. Spoon the black bean filling onto one half (about 1/3 cup not packed). Then sprinkle the filling with cabbage and about 1 tablespoon cheese. Fold over the tortilla and gently press it down. Repeat for the remaining tortillas and filling.
Bake the tacos for 5 minutes. Then flip them over. Bake for another 10 minutes. Flip them again and bake for 5 minutes until they are golden brown and crisp on the outside.
To make the avocado crema, combine the avocado, yogurt, lime juice, water, cilantro and pinches of salt & pepper in the bowl of a food processor. Puree until smooth. (You may need to add another tablespoon of water to thin it out.)
Arrange the tacos on a serving plate. Top with chopped cilantro and serve with avocado crema on the side or drizzled over the tacos.