In a medium saucepan combine tomatoes, salsa, chili powder, and cocoa powder. Bring to boiling; reduce heat. Simmer, uncovered, about 10 minutes or until slightly thickened, stirring occasionally and mashing with the back of a spoon. Season to taste with salt and black pepper; set aside.
Meanwhile, preheat oven to 350 degrees F. Coat a 2-quart rectangular baking dish with cooking spray; set aside. Stack tortillas; wrap tightly in foil. Bake about 10 minutes or until warm.
In a large skillet heat oil over medium heat. Add onion; cook for 2 minutes. Add root vegetables and cumin; cook and stir for 3 to 4 minutes or until vegetables are crisp-tender. Remove from heat. Stir in half of the tomato mixture, the black beans, 3/4 cup of the cheese, and half of the cilantro.
Divide black bean mixture among warm tortillas; roll up tortillas. Arrange rolled tortillas, seam sides down, in the prepared baking dish. Spoon the remaining tomato mixture over enchiladas. Sprinkle with the remaining 1/2 cup cheese. Bake, uncovered, for 15 to 20 minutes or until heated through.
Drizzle with the 1/4 cup Mexican crema. Bake for 5 minutes more. Sprinkle or serve with the remaining cilantro. If desired, serve with salsa, additional crema, and/or additional shredded cheese.