Place pork in a heavy-duty zip-top plastic bag. Add 2 tablespoons hot sauce, honey, and apple cider. Seal bag, and gently shake to coat. Marinate in refrigerator at least 8 hours. Drain, reserving marinade.
Heat oil in a large nonstick skillet. Add onion and apple; sauté 6 to 8 minutes or until tender. Stir in 1/4 teaspoon hot sauce and salt.
Insert meat thermometer into thickest part of pork. Place pork on grill rack coated with cooking spray; grill 10 minutes on each side or until thermometer registers 160°. Remove from grill, and keep warm.
Boil reserved marinade in a small saucepan 1 minute.
Slice pork thinly, and place on bottom halves of rolls; top evenly with onion mixture and marinade. Cover with top halves of rolls.