In a medium bowl, mix together the onion, pepper, black beans, corn, spices, meat (if using), and just 1/2 cup of the cheese. Pour about a cup of salsa (half a jar) into the bottom of the slow cooker and spread it around evenly.
Scoop about 1/3 cup into one of the tortillas, roll it up, and nestle it into the bottom of the crock pot. Repeat with the half of the remaining filling, rolling tortillas until the entire bottom of of the crock pot is filled. Spread another cup of salsa over this layer and sprinkle it with another 1/2 cup of cheese.
Continue with the remaining filling and tortillas to create a second layer. Top with another cup of salsa, but reserve the remaining 1/2 cup of cheese for later. Place the lid on the slow cooker and cook on HIGH for 2-4 hours. In the last 15 minutes of cooking, sprinkle the leftover cheese over the top and let it melt.
Serve the enchiladas with the remaining salsa. Leftovers will keep for up to a week in the refrigerator.