Prep the marinade: In a blender, combine garlic, onion, vinegar, salt, pepper, cumin, oregano, and paprika. Blend until smooth.
Rub it down: Coat the lamb generously with the marinade. Let it sit for at least an hour, preferably overnight.
Wrap and place: Line the bottom of your slow cooker or Dutch oven with maguey (or banana) leaves. Place the marinated lamb on top and wrap with more leaves. Add water around the meat.
Cook low and slow: Cover tightly and cook on low for 8 hours (or bake at 300°F for 6–7 hours). The meat should shred easily.
Serve it up: Remove meat, shred it, and serve with warm corn tortillas, salsa borracha, onions, cilantro, and lime.
Don’t forget the consomé: Strain the cooking juices, add chickpeas and rice, and season to taste. Serve in small cups alongside your tacos for the full experience.