1. Trim and discard fat from tenderloin. Rinse meat and pat dry. Cut crosswise into 1/2-inch-thick slices and place in a heavy plastic food bag.
2. Rinse onions and trim and discard ends. From white ends, roughly slice enough onions to make 1/3 cup; cut remaining green tops into 1 1/2-inch lengths and set aside. In a blender or food processor, whirl roughly sliced onions, soy sauce, honey, garlic, and pepper until smooth. Pour marinade over pork and seal bag; turn to mix well. Let stand 10 to 15 minutes.
3. Meanwhile, in a 2- to 3-quart pan, combine rice and 2 3/4 cups water. Bring to a boil over high heat and cook until most of the water is absorbed, 7 to 10 minutes. Reduce heat to low, cover, and simmer until rice is tender to bite, 10 to 15 minutes longer.
4. While rice cooks, lift pork from marinade; reserve marinade. Thread equal portions of meat onto 4 metal skewers (8 to 10 in.) so slices lie flat, with 1 reserved green onion piece perpendicular to skewer between each 2 meat slices.
5. Set skewers in a single layer on a rack in a foil-lined 10- by 15-inch broiler pan; broil 3 inches from heat, turning once, until pork is browned on both sides and no longer pink in the center (cut to test), 6 to 8 minutes total.
6. In a 1- to 2-quart pan over high heat, bring reserved marinade, any pan juices, marmalade, and vinegar to a boil. Pour into a bowl.
7. Serve skewers with lettuce leaves, rice, and marmalade-vinegar sauce. Place a spoonful of rice and a piece of meat on a lettuce leaf, drizzle with sauce to taste, and wrap up to eat.