Mix the tamari sauce, honey, lime juice and a teaspoon of sesame oil in a baking pan 9x13 inches. Coat each tuna steak on all sides in the sauce.
Heat up oil in a large pan on medium high flame until fully hot.
Mix the two types of sesame seeds in a bowl.
Take the tuna out of the sauce and save the sauce in the baking pan. Coat both sides of the tuna steaks in the seeds. Cook each piece in the pan for 1-2 minutes per side.
Cook the marinade from the baking pan into the pan for 30 seconds and pour it over the steaks. Serve with Harlan's peanut sauce on the side.