Pierce sweet potatoes with a fork a few times and place in microwave and microwave on high for 4-6 minutes or until cooked though. Once cooked, remove the skins and place potatoes in a bowl and mash with a fork. Keep aside.
In a separate bowl, add black beans, cumin, chili powder and red pepper flakes. Stir to combine then set aside.
In another bowl, beat egg whites together. Spray a skillet with nonstick cooking spray and place over medium-low heat. Add in egg whites and cook. Fold every few minutes to get fluffy eggs. Once cooked, remove from heat.
Lay out warm tortillas and evenly distribute and spread mashed sweet potato on each. Evenly distribute egg whites, diced avocado, black beans, and shredded cheese on each tortilla. Next drizzle about a tablespoon of enchilada sauce in each. Season with salt and pepper, if desired. Tuck ends in, then roll up burritos. To warm up, place on baking sheet in the oven at 300 degrees for 5-10 minutes. Serve with sour cream, greek yogurt, salsa, or hot sauce.
