In a medium saucepan combine black beans, salsa, chili powder and cumin. Simmer mixture for about 5 -10 minutes, stirring occasionally. Slightly mash beans if desired.
Meanwhile in a food processor pulse together avocado, Greek yogurt, cilantro, lime juice and garlic until cilantro is finely minced. Season with salt and pepper to taste (if you want the sauce thinner you can add in 1 Tbsp water).
To assemble tacos, on each tortilla layer black bean mixture, avocado cilantro lime crema, lettuce, cheese and tomatoes. Serve immediately.
Refrigerated salsa can be found in the produce section or in the refrigerated latin foods section of the grocery store. If using homemade use one that includes tomatoes, onions, cilantro and garlic.
This is about the top 1/3 portion of one medium bunch of cilantro, so use mostly leaves and some stem.
This is my preferred method for cooking corn tortillas for tacos (although those pictured were just warmed and browned with a flame): I brush the tortillas lightly with olive oil then cook them in a skillet over medium-high to medium heat until they begin to get golden brown spots on the bottom then flip and cook opposite side until lightly browned.
Nutrition does not include lettuce, cheese and tomatoes.