Whisk together peanut oil, soy sauce, balsamic vinegar, green onions, garlic, brown sugar, ginger, red chile flakes, sesame oil, and salt. Place fish in a glass dish, and pour marinade over all. Cover with plastic wrap, and refrigerate for 4 to 6 hours.
Preheat barbecue or gas grill.
Oil the grill rack, and adjust height to 5 inches from coals. Remove salmon from marinade, and place on grill. Grill for 10 minutes per inch of thickness, measured at thickest part, or until fish just flakes when tested with a fork. Turn halfway through cooking.