Brown the ground beef with the onions and garlic in a large skillet over medium-high heat. Drain the fat. Add the cumin and salt and pepper, to taste. Stir to combine. Stir in the beans and green chiles until combined. Turn off the heat and set aside
If using corn tortillas, in a small skillet over medium heat, heat some canola oil. Lightly fry the tortillas just until soft. Do not crisp. Drain on a paper towel-lined plate. Repeat until all the tortillas have been fried. Skip this step if using flour tortillas.
Heat oven to 350°F (180°C). Spread 1/2 cup of the enchilada sauce evenly along the bottom of a 9- by 13-inch baking dish
To assemble the enchiladas, lay tortilla on a flat surface and add 1 tablespoon of the enchilada sauce to each tortilla. Then, add 2 or 3 tablespoons of the beef mixture to the center of the tortilla. Top with about 1/4 cup cheese. Roll the tortilla and place seam side down onto prepared baking dish. Repeat with remaining tortillas and beef mixture. Top with remaining enchilada sauce and cheeses.
Place into oven and bake until bubbly, about 20 minutes.
Serve immediately. Garnish with cilantro and avocado, if desired