Season tuna steak with salt and pepper to taste.
In a medium bowl, whisk the olive oil, soy sauce, lemon juice, minced garlic, grated ginger, basil, green onion, and herb of choice. Add black pepper and salt to taste.
Place the tuna steaks in a shallow dish or resealable ziploc bag. Pour the marinade over the tuna steaks, coating them well.
Tightly cover or seal with plastic wrap and place in the fridge for 30 minutes to 1 hour for optimal flavor.
Clean and oil the grill grates to prevent sticking. Preheat your gas or charcoal grill to medium-high heat (375-400°F/190-205℃).
Remove any particles from the tuna and let the excess marinade drip off.
Directly place on the hot grill grates and grill for about 2-3 minutes on each side. If you like your tuna rare to medium, grill to the desired doneness.
Once the tuna steaks are grilled to your desired doneness, carefully remove them from the grill.
Sprinkle sesame seeds over them for extra crunch and a nutty flavor.
Serve the grilled tuna steaks with lemon wedges on the side for a zesty touch.