In a medium saucepan, heat the oil.
Add the garlic and cook over moderately high heat, turning occasionally, until lightly browned, about 1 minute.
Stir in the oregano, cumin, pepper and cloves and cook until fragrant, about 1 minute.
Add the chiles and cook, stirring, until blistered in spots, about 30 seconds.
Add the pineapple juice, vinegar and achiote paste and bring to a boil.
Remove from the heat and let stand for 5 minutes.
Transfer the chile mixture to a blender and puree until smooth. Season with salt.
Place the pork in a glass baking dish, add the marinade and turn to coat.
Cover and refrigerate overnight.
Preheat a grill to high. Brush the onion with oil.
Grill over high heat, turning once, until lightly charred and softened, 3 to 5 minutes.
Transfer to a carving board and tent with foil.
Remove the pork from the marinade. Grill over high heat until lightly charred and just cooked through, 2 to 4 minutes.
Transfer to the carving board and let rest for 5 minutes.
Chop the onion then cut the pork into thin strips and transfer to a bowl. Season with salt.
Serve the Al Pastor over the corn tortillas, top with chopped cilantro and plantain tidbits and salsa verde.
Garnish with lime wedges.