How to Make It
Heat oven to 400° F. Heat 1 tablespoon of the oil in a large skillet over medium-high heat. Add the onion and cook, stirring, until softened, 3 to 5 minutes. Add the beef and cook, breaking it up with a spoon, until browned, 2 to 3 minutes. Mix in the beans and 1 cup of the Cheddar.
Spread 1 cup of the enchilada sauce in the bottom of a 9-by-13-inch baking dish. Roll up the beef mixture in the tortillas and place the rolls seam-side down in the dish. Top with the remaining cup of enchilada sauce and cup of Cheddar. Bake until the Cheddar is brown in spots, 10 to 15 minutes.
Meanwhile, wipe out the skillet and heat the remaining tablespoon of oil over medium-high heat. Add the zucchini and ¼ teaspoon salt and cook, tossing occasionally, until tender and golden, 8 to 10 minutes. Top the enchiladas with the sour cream, salsa, and cilantro and serve with the zucchini.