Remove the stems and shake the seeds from the dried guajillo chili peppers. Soak the guajillo chili peppers in hot water for 20 minutes or until they become soft. Drain the water from the soaked peppers.
In a blender, add the softened guajillo peppers, garlic cloves, and the can of chipotle peppers in the adobo sauce, honey, a packet of Sazon, and only the juice from the canned pineapple. Blend until smooth.
Pour the sauce over the thinly sliced pork, mix to combine, and refrigerate for at least two hours or overnight.
When ready to cook, add the marinated pork to a slow cooker set on low and let slow cook for 6-8 hours.
While the pork is slow cooking, evenly spread the pineapple chunks on a baking sheet. We sliced our chunks in half to make them smaller. Bake the pineapple at 400 degrees until the juice has evaporated and the pineapple is slightly golden. Remove the pineapple pieces and set aside.
To serve, heat tortillas and fill them with the Al Pastor. Top tacos with prepared pineapple chunks and any of your favorite toppings. Serve immediately.