In a small bowl, combine marmalade, soy sauce, mustard, and hot pepper flakes. Stir in water until well blended. Set aside.

Season pork chops with black pepper. In a large nonstick skillet, heat oil over medium-high heat. Add chops; cook until lightly browned, turning once, about 2 minutes per side.

Spoon marmalade mixture over chops; bring to a boil. Reduce heat to low. Cover and simmer until tender, about 15 minutes. Stir in green onion. Place on serving plates and garnish with orange slices. Serve with any pan juices on the side.