Place dried guajillo peppers in a shallow bowl with hot water for 15 minutes to rehydrate them.
Coat the inside of the slow cooker crock with oil.
When peppers are hydrated, place them in a food processor or blender along with ½ cup of the soaking juices & seeds (optional: if you like milder flavors, remove the seeds.) Add chipotles + garlic + beef broth + 3T lime juice (~2 limes) +apple cider vinegar + cumin + oregano + ground cloves and blend until smooth.
Pour the sauce over the roast and turn to coat. Close the lid and cook on low for 8-10 hours or on high for 4-5 hours.
When roast is fully cooked, shred with two forks and toss in the sauce.
Serve as lettuce wraps or on corn tortillas. Garnish with sliced radish, queso fresco, cilantro, and lime wedges.