Don't overblend the black bean filling. Use the pulse function instead of continuously blending so the filling still has texture.
Cook the tortillas in a frying pan for 30 to 60 seconds to get the best taco texture and flavor.
Serve the tacos with lime-pickled onions and chipotle crema, or with sour cream and store-bought salsa.
The black bean filling, pickled onions, and chipotle crema can be made in advance and stored separately in the fridge.
The assembled tacos can also be made a day or two ahead and refrigerated, then baked when ready to eat.
The taco filling also freezes well, as long as it's defrosted before reheating.