SEASON the meat with the salt and pepper and place in a 5- to 6-quart slow cooker.
PLACE the guajillo chiles in a small saucepan and cover with boiling water. Let stand until softened, about 10 minutes. With a slotted spoon, transfer the chiles to blender or food processor.
ADD the broth, tomatoes, vinegar, onion, chiles in adobo (or smoked paprika), garlic, cumin, oregano, cinnamon, ginger, and cloves to the blender. Cover and blend until smooth.
POUR the sauce over the meat and stir to combine.
COVER and cook on low for 8 to 9 hours, or on high for 4 to 5 hours.
CAREFULLY transfer the meat to a cutting board.
STRAIN the cooking liquid through a fine-mesh strainer into a large bowl.
RETURN 1 cup cooking liquid to the slow cooker; discard the remaining liquid and the solids.