Rehydrate the anchos and chipotles in a bowl and cover with hot, boiling water. Soak the chiles until they are soft, about 20 minutes.
Add the chiles, paprika, oregano, cinnamon and garlic to a food processor. Pour in the oil and process until smooth. If the puree is too thick, add a tablespoon or 2 of the chile soaking liquid to thin to desired consistency.
Place the lamb in a roasting dish and sprinkle all over with salt and pepper. Pour the puree on top, cover and marinate in the fridge for 3 to 4 hours.
Preheat the oven to 275 degrees F. Thaw the banana leaves (if frozen) by running them under warm water. Line a turkey roaster or braising dish with the banana leaves, slightly overlapping them on one another.
Remove the lamb from the marinade and place on the banana leaves. Wrap up the lamb with the banana leaves, tucking in the edges so it is completely covered. Add 1 1/2 cups water to the baking dish, then cover the entire pan with aluminum foil.
Bake until the meat is tender and falling apart, 4 hours. Remove the foil and open the banana leaves. Shred the lamb with a fork and season with salt and lime juice. Serve with the warm flour tortillas, cilantro leaves, queso fresco, radishes and onions and pair with the Malbec.
Recipe courtesy of Guy Fieri