1. Preheat oven to 400°.
2. Combine chiles and 2 cups water in a saucepan; bring to a boil, reduce heat, and simmer 5 minutes. Remove from heat; let stand 5 minutes. Drain chiles in a colander over a bowl, reserving 1 cup cooking liquid.
3. Heat oil in a medium saucepan over high heat. Add onion; saute 1 minute. Reduce heat to medium; add garlic and salt. Cook 5 minutes or until golden, stirring occasionally. Add broth and next 3 ingredients (through cumin); cook 8 minutes or until thickened, stirring occasionally.
4. Pour onion mixture into a blender; add chiles and reserved liquid. Remove center piece of blender lid (to allow steam to escape); secure lid on blender. Place a clean towel over opening in lid. Blend until smooth; stir in lime juice and red pepper.
5. Combine the beans, 1 cup cheese, and half the green onions in a bowl. Spread 1/2 cup sauce in the bottom of a 13 x 9-inch glass or ceramic baking dish coated with cooking spray. Warm tortillas according to package directions. Spoon 3 tablespoons bean mixture down center of each tortilla; roll up. Place, seam-side down, in prepared dish. Pour remaining sauce over filled tortillas. Top with the remaining cheese. Bake at 400° for 15 minutes or until lightly browned. Sprinkle with remaining green onions; serve with sour cream.