Cook noodles according to package directions; drain. Set aside.
Sprinkle both sides of tuna steaks with salt and pepper.
Heat butter and oil in deep 10-inch skillet; stir in garlic. Add tuna steaks. Cook over medium heat, turning once, 5-6 minutes or until browned. Stir in vinegar, teriyaki sauce, and ginger root. Reduce heat to medium-low; cook 8-10 minutes or until internal temperature reaches 145ºF and fish flakes easily with a fork. Use a spatula to remove tuna from skillet; keep warm.
Add onions and carrot to the sauce in skillet. Cook over medium heat 1 minute. Stir in cooked noodles and rice. Increase heat to medium-high; cook, stirring constantly, 2-3 minutes or until heated through.
Serve hot tuna steaks on fried noodles and rice.