Cut pork in two and rub with salt, cumin, and oregano.
Heat oil in a bottom of a pressure cooker set to the saute function. Add the garlic and red chili pepper and cook until fragrant. Add the pork and onions and brown on all sides. Add the orange juice and lime juice, cover, and cook on high pressure for 20 minutes followed by a 15 minutes natural release.
Slice pork thin and reserve some of the juices. Brush juice on the inside of the bread.
On the bottom slice of the loaf, layer on 3 slices of cheese, ham, pork, sprinkle with salt and pepper, 3 more slices of cheese, pickles, and spread the mustard on the inside of the top bread loaf. Cut the sandwich in half.
Heat a grill pan or skillet over medium heat and brush with oil. Place the sandwiches on the pan and place another heavy pan on top to weigh it down. Cook on both sides for 6-7 minutes until cheese is melted and grill marks form on bread. Serve immediately.