In a bowl, whisk together soy sauce, sesame oil, rice vinegar, honey, minced garlic, and grated ginger.

Place the tuna steaks in a shallow dish and pour the marinade over them. Let marinate for 10 minutes.

Heat a skillet over high heat. Remove tuna from marinade and sear each steak for 1-2 minutes on each side for rare, or longer to desired doneness.

Remove tuna from skillet, let rest for a minute, then slice against the grain. Garnish with sesame seeds and green onions before serving.