In a medium pan, heat the oil over medium-high heat. Once hot, add the onion and garlic and saute until translucent, about 3 minutes.
Add the black beans, cumin, and salt and pepper to taste. Use a fork to slightly mash the beans and cook until heated through, about 3 minutes.
To make the cabbage slaw, mix 2 tsp. of olive oil and lime juice in a medium bowl. Add the coleslaw, green onions, cilantro and toss to coat. If desired, you can also add the mayonnaise for a creamier slaw. Season with salt and pepper, to taste.
Heat 1 tsp. of olive oil in a large nonstick skillet over medium heat. Add three tortillas in a single layer. Once golden brown, flip, then spoon ¼ of the bean mixture onto each tortilla and cook for 1 minute or until golden brown.
Repeat with the remaining tsp. of oil and tortillas. Fill the tacos with feta and slaw. Serve with hot sauce, lime wedges and sour cream.
