Pour vinegar, brown sugar, orange juice, garlic, olive oil, salt and pepper, into a large zip-top bag. Seal and shake to combine. Cut pork chops into 1 1/2 inch cubes, add to the bag, seal and refrigerate for 1 hour or up to one day.
Soak bamboo skewers in water for 30 minutes. Remove pork from the marinade. Strain marinade to remove the garlic. Pour marinade into a small saucepan. Bring marinade to a boil over medium-high heat, reduce heat to a simmer. Simmer until slightly thickened and reduced by half, about 5-7 minutes. Reserve.
Skewer pork, apples and onions, sprinkle with salt and pepper. Heat the grill to medium-high. Oil grill to keep the skewers from sticking. Place skewers on the grill, cook for 4 minutes, turning them a quarter turn every 4 minutes, for a total of 16 minutes. If using your broiler, broil for about 10 minutes total, flipping once. Do not overcook the pork, or it will become tough. Serve over rice and drizzle with reduced marinade.