Brush both sides of orange slices and salmon with 2 Tbsp oil. Season salmon with salt and pepper to taste.
Grill orange slices, turning once; transfer to plate. Grill salmon, skin side down, for a bout 5 minutes or until skin is crisp. Turn and grill for 1 minute, then turn again and grill until cooked to desired doneness, about 2 minutes. Cover salmon with foil to keep warm.
In saucepan, combine remaining 10 Tbsp oil, basil and mint. Warm over medium-high heat for about 2 minutes. To serve, drizzle salmon with herbs and oil; top with orange slices.