Prepare the marinade:

1. Combine together the crushed garlic, salt, pepper, juices, onion, and oregano in a small bowl. Let sit at room temperature for 30 minutes, allowing the flavors to meld.
2. In a medium saucepan, heat the olive oil until hot but not sizzling. Stir in the garlic mixture until well blended. Allow to cool.

Roast the pork:

1. Place the pork roast in a roasting pan. Puncture the surface of the pork all over with a fork. Pour the marinade over the pork, cover, and refrigerate for at least 2 hours.
2. Preheat oven to 375 degrees F.
3. Cook the pork, uncovered, for 20 minutes at 375 degrees, then lower temperature to 225 degrees F and cook until the meat is tender, cooked through, and pulls apart easily.
4. Slice pork.

Assemble the Cubano sandwiches:

1. Preheat a cast-iron skillet over medium heat.
2. Cut bread loaf in half horizontally, and then into 6-inch portions. Spread inside of bread with butter. Toast the buttered inside of the bread in the heated skillet until lightly golden.
3. Remove from skillet and layer the ingredients on the bottom piece of bread in this order: pork, ham, cheese, and then pickles. Spread yellow mustard on the inside of the top bun and place on top of the sandwich. Brush the outside of the sandwich with butter and grill the sandwiches for a few minutes per side, until golden brown and the cheese has melted.
4. Repeat with remaining sandwiches. Enjoy!