In a food processor or with a fork and knife, mash the four chipotle peppers until fairly smooth. In a bowl, whisk together the pineapple juice, vegetable oil, achiote paste, chipotle peppers (with some of the adobo sauce from the can), cloves of garlic (minced) and salt. Once it is whisked together, set aside. Remove the pork chops (or loin) from the package and cut with a sharp knife into one inch cubes. Add the pieces of pork to the marinade mixture. Let the pork sit with the marinade for several hours, or overnight. When ready to cook the pork, heat a pan or cast iron skillet to high heat. Once the pan is hot, add some olive oil or more vegetable oil to the pan. Remove the pork from the marinade and add the pieces of pork to the pan (the less marinade the goes into the pan, the more golden brown you can get your pork pieces). Let the pork sit on the hot pan until it starts to get golden brown and cooked. Turn the pork pieces once they are cooked, and eventually just saute them on all sides to get them cooked through to the center. They don't have to be totally golden on each side, but if you have a nice char on at least one side, it will look more apptizing. Season the pork with salt and pepper. Serve the tacos with the Pineapple Salsa, cojita cheese crumbles and cilantro.