Preheat the oven to 200°F. Place a baking sheet on middle rack while it heats.

Rinse and drain the black beans. Chop the cilantro and green onions. Cut one lime into wedges and set aside. Squeeze the juice from the remaining lime.

Transfer the black beans to a medium mixing bowl and add the chopped cilantro, green onions, lime juice, olive oil, chili powder, garlic powder, salt, and feta. Stir well to combine.

Heat a large nonstick skillet over medium-high heat. Add about 1 teaspoon of oil and place two tortillas in the skillet. When tortillas are warm, place 1/4 cup of the bean mixture down the center of each. Fold each tortilla over to make a taco (you may have to press gently with a spatula to get the tortillas to stay folded). Cook until golden brown on bottom, 1-2 minutes. Flip the tacos over and cook for an additional 1-2 minutes.

Transfer tacos to the baking sheet in the oven to keep warm.

Repeat the steps until all 12 tortillas are filled and cooked.

Transfer the tacos to a platter with the lime wedges and scatter cilantro leaves on top. Serve warm with sour cream and hot sauce, if desired.