Marinate the tuna: In a shallow dish, mix soy sauce, sesame oil, lime juice, garlic, and ginger. Add the tuna steaks and let them sit for about 10 minutes.
Prepare the coating: Spread the sesame seeds on a plate. Remove the tuna from the marinade, pat dry, and season lightly with salt and pepper. Press each side of the tuna into the sesame seeds to coat evenly.
Heat the pan: Place a cast iron or heavy skillet over medium-high heat. Add the neutral oil and let it heat until shimmering.
Sear the tuna: Carefully place the tuna steaks in the pan. Cook for about 45–60 seconds on each side for rare centers, or up to 90 seconds if you prefer medium-rare.
Rest and slice: Remove the tuna from the pan. Let it rest for 1–2 minutes, then slice against the grain into thick strips.
Serve: Arrange the slices on a platter with lime wedges and your favorite dipping sauce.
