Bring 3 cups of water to a boil. Add the ancho chile and guajillo chili peppers, and bring down to a simmer. Simmer for 10 minutes, until softened and rehydrated. Remove the chiles from the water and set aside.
To a food processor or blender, add the the softened and rehydrated chili peppers, 1 cup of the diced pineapple, chipotles in adobo sauce, garlic, onion, orange juice, and pineapple juice. Process until you get a smooth marinade. Then, add dried oregano, cumin, paprika, salt, and pepper and pulse a few more times to combine. Taste and adjust the seasoning if needed.
Poke the pork all over with a fork to allow the flavor to penetrate better.
Slow cook: Into a large slow cooker, add the pork, the marinade, and the remaining 2 cups of diced pineapples. Mix to combine. Cook on HIGH for 4 hours or LOW for 8 hours. 20 minutes before it’s done, transfer the meat to a large plate and shred with a fork. Return the meat to the slow cooker to finish cooking, until the cooking time is up.
Assemble the tacos: Serve the meat on warmed up tortillas, and top with cilantro, diced onions, diced pineapples. Serve with lime wedges. Enjoy!