Mix soy sauce, sesame oil, lime juice, grated ginger, and minced garlic in a bowl. This will be your marinade.
Sprinkle salt and pepper on both sides of the ahi tuna steaks to season them.
Place the ahi tuna steaks in a shallow dish or a resealable plastic bag. Pour the marinade over the steaks, ensuring they are well-coated.
Refrigerate the steaks for at least 30 minutes, allowing the marinade to infuse the flavors.
Heat a skillet or grill over medium-high heat. Sear the marinated ahi tuna steaks for about 2 minutes on each side. You want them cooked on the outside but still pink inside.
Remove from heat and let the steaks cool for a couple of minutes. Slice them against the grain for the best texture.