Make the marinade. Saute sliced white onion in a medium saucepan with 1 tablespoon cooking oil. When onion has developed a nice char, add smashed garlic cloves and brown for about 1-2 minutes. Then add the dried guajillo and ancho peppers and sauté for 1-2 minutes. Add the remaining marinade ingredients, stir together, and cook on low heat covered for about 10 minutes. Then remove from the heat and allow the liquid to cool.
Pour the marinade liquid (with the peppers, onions, bay leaves, etc) into a blender cup. Blend until smooth.
Pour the marinade into a wire mesh strainer to strain out any chunks. Then pour the strained liquid into a large bowl with the cut pork. Stir so that the pork is covered in the marinade. Marinate the pork in the fridge for 4 hours.
Heat griddle to about 450-475 degrees F. Add about 1 tablespoon of cooking oil to the heated surface and spread it around in an even layer with your spatula.
Add the marinated pork pieces to the heated griddle, straining as you go so there is not too much moisture on the griddle. Spread out the pork to ensure that each piece of pork is in contact with the griddle surface. Cook pork untouched on the first side for about 5-6 minutes, or until a nice crust develops. Then, sauté the pork together, cook an additional 2-3 minutes, and move to the side of the griddle to make room for the pineapple.
Add the pineapple to the griddle and sauté for about 4-5 minutes, or until a nice golden color develops and the sugars are slightly caramelized. Then, remove pineapple from the griddle.
When pork is cooked through, transfer to a serving bowl.
Build the pineapple pork tacos. Add pork and pineapple pieces to warm corn tortillas. Top with your favorite taco toppings and serve.