Preheat oven to 375°F (190°C).
Lay zucchini slices on a clean surface and sprinkle with salt. Let them sit for 10 minutes, then pat dry with a paper towel.
In a bowl, mix shredded chicken (or black beans), cumin, garlic powder, onions, salt, and pepper.
Spread a small amount of enchilada sauce in the bottom of a baking dish.
Spoon some of the chicken mixture onto each zucchini slice and roll tightly.
Place rolls seam-side down in the baking dish and top with remaining enchilada sauce and cheese.
Bake for 20-25 minutes until the cheese is melted and bubbly.
Garnish with cilantro and serve with sour cream or avocado if desired.