Heat your oven to 275º. Place your tortillas on a baking sheet. Place them in the oven and let warm until pliable. You may need to rearrange the tortillas so they all get evenly warm through.
Spray 12 large muffin tins with cooking spray. Once the tortillas have warmed enough to be pliable, place one tortilla into each muffin tin. They will have to be folded up a bit to fit.
Raise the oven temperature to 350º
Meanwhile, brown the ground beef, onions, garlic and jalapeños. Drain off the grease if needed. Once browned add the tomato, black beans and corn. Cook on low for 10 minutes.
Add the enchilada sauce, taco seasoning and 2 tablespoons of shredded cheese to help bind.
Fill each tortilla cup with spoonfuls of filling. Fill to the top of the muffin tin. Place a spoonful or two of shredded cheese on each of the tortilla cups.
Place in your heated oven until cheese melts and tortilla edges are crisp, about 10 minutes. *one note: for extra crispiness the tortilla cups can be heated in the oven before placing the filling in the cups, then filled and reheated.
Chop the avocados and squeeze lime over them. Garnish the tortilla cups with the avocados and minced cilantro. Serve hot.