Combine chopped onion and honey in a medium nonstick skillet, and place over medium heat. Cook 12 minutes or until golden brown, stirring occasionally. Add red wine and the next 4 ingredients (wine through mirin); cook 10 minutes. Stir in diced pineapple, and cook 5 minutes. Keep warm.
Thread 3 mahimahi pieces, 3 pineapple cubes, and 3 bell pepper pieces alternately onto each of 8 (12-inch) skewers. Sprinkle kebabs with sage, salt, and black pepper. Place the kebabs on a grill rack coated with cooking spray; grill kebabs 15 minutes or until fish is done, turning every 5 minutes. Serve with pineapple sauce. Sprinkle with chives, if desired.