This recipe provides instructions for making tacos al pastor with the following key steps: 1. Boil and simmer dried chiles to make a paste, then combine with onion, pineapple juice, vinegar, garlic and cumin in a food processor. 2. Bring the chile mixture to a boil and cook to reduce raw onion flavor. Season with adobo. 3. Marinate pork in the chile marinade along with pineapple chunks for 12-24 hours. 4. Strain and cook the marinated pork until browned and cooked through. Serve in warm tortillas with onion, cilantro and lime.