Preheat your oven to 400 F.
Add 1 TBSP oil to a skillet over medium heat, followed by the black beans (both cans, rinsed and drained). Add salt and pepper to taste, cumin and chipotle powder/chili powder. Stir and cook for about 5 minutes, until the beans get a little soft. Then add the spinach and cover the pan to let the spinach steam and cook down, about 5 minutes. Stir the spinach and beans together, then add 1 TBSP enchilada sauce and 3/4 cup shredded cheese. Stir it all up turn off the heat.
Spray a 9x13 baking dish with cooking spray. Pour 1/2 of the remaining enchilada sauce inside the pan and spread it around the bottom with a spatula.
Assemble the enchiladas: You're making 6 total enchiladas (2 per serving) so add about 1/3-1/2 cup of filling to each tortilla. Add filling to the middle and roll up the tortilla, then place it seam down in the prepared baking dish. Repeat the process 5 more times.
Pour the remaining enchilada sauce over the tortillas, followed by the remaining cheese (1/2 cup). Bake uncovered for 15-20 minutes, until you can see the sauce bubbling a bit.
Let the enchiladas cool for 15-20 minutes, then carefully divide them between 3 meal prep containers. Top with cilantro if using.