How to Make It
In a small bowl, mix the chives with the basil and thyme. Rub the tuna steaks with olive oil, then coat with the 2 tablespoons of soy sauce. Season lightly with salt and pepper. Press the herbs onto both sides of the steaks. Sprinkle both sides with the sesame seeds. Refrigerate for 30 minutes.
Light a grill or preheat a grill pan. Grill the tuna steaks over high heat, turning once, until charred on the outside and medium-rare within, about 4 minutes. Cut into thick slices and serve, passing more soy sauce at the table.