How to Make It
Preheat the oven to 350°F. In a blender, puree the salsa and reserve.
In a large heavy skillet, heat the oil over medium high heat until hot, then stir in the on-ion, garlic, 1/2 teaspoon salt and 1/4 teaspoon pepper and cook, stirring occasionally, until golden, about 6 minutes. Stir in the chicken and black beans along with their juices, and cook until the chicken is cooked and the liquid is slightly thickened, about 5 minutes. Season the filling with salt and pepper to taste.
Divide the filling between the tortillas. Roll each tortilla into a cylinder and place, side-by-side in a baking dish. Pour the salsa over the tortillas and sprinkle with the cheese.
Bake the enchiladas until the filling is hot and the cheese is melted, about 15 minutes. Serve.