Place the meat in a bowl. Add the adobo sauce, pineapple juice, and a pinch of salt. Mix to coat on all sides, cover the bowl, and leave the meat marinating overnight or for at least 4 hours.
Heat the oil in a no-sticking pan over medium heat. Place the marinated pork slices on a single layer and pan fry on all sides until cooked through and the meat is slightly charred on the sides (read note 1).
Cut the bolillo rolls in half and spread each piece with mayonnaise and mustard.
Arrange one slice of cooked al pastor pork on each bottom side of the bolillos.
Then add a few slices of avocado, sliced onion, and tomato slices.
Season with a pinch of salt then top with a handful of shredded lettuce.
Finish with some diced pineapple and pickled jalapeños on top.
Close each torta with the other half of the bolillo rolls. You can also cut the sandwich in half so it will be easier to eat, then serve or pack for later.
Notes
Cooking the meat usually takes 2-3 minutes per side, but it depends on the thickness of the pork slices.
You can use homemade adobo sauce or store-bought if you prefer.