Preheat: If baking the tacos, preheat oven to 400°F.
Warm tortillas: Wrap the tortillas in a lightly damp paper towel and microwave for about 1 minute to make them soft and pliable.
Oil tortillas (for baking): If baking the tacos, arrange the tortillas on a baking sheet. (You can use parchment for easier cleanup but it's not required.) Brush or lightly spray each tortilla with oil to help them crisp up. Then, flip them over so the oiled side is facing down. If pan-frying the tacos, skip this step.
Make the tacos: Spread a heaping spoonful of the black bean mixture on one half of each tortilla. Optionally, spread some cheese over the bean mixture. Fold the tortilla over to form a taco. Flip the taco over to help it stay closed while baking.
For baked tacos: Bake tacos in preheated 400°F oven for 15-20 minutes, removing them from the oven and carefully flipping them at around the 7 minute mark.
For pan-fried tacos: Heat a lightly oiled skillet over medium heat. Place folded tacos in the skillet and cook for 2–3 minutes per side, pressing gently with a spatula, until golden and crispy.