1Stir the orange juice, lime juice, garlic, oregano, cumin and salt together in a zip-top bag or shallow dish. Add the pork tenderloin, turn it to coat, and let it marinate at room temperature for 30 minutes, turning once.
2Heat the olive oil in a large skillet over medium-high heat. Lift the pork out of the marinade, pat it dry, and discard the marinade. Sear the pork for 2 to 3 minutes per side until deeply browned all over.
3Lower the heat to medium and keep cooking, turning now and then, for 10 to 12 minutes more, until a thermometer in the thickest part reads 145°F. Rest on a cutting board for 5 minutes, then slice thinly. Wipe out the skillet.
4Spread mustard on the cut sides of every roll. Layer the bottoms with swiss cheese, ham, sliced pork, pickle chips, and one more slice of swiss on top so the cheese glues everything together. Close the sandwiches and spread the softened butter on the outside of the rolls.
5Heat the clean skillet over medium heat. Set in as many sandwiches as fit, then weigh them down with a heavy pot or a second skillet. Press and toast for 3 to 4 minutes, until the underside is golden and crisp.
6Flip each sandwich, press again for 3 to 4 minutes until the cheese is melted and the bread is crackly. Repeat with any remaining sandwiches. Slice on the diagonal and serve hot.