If desired, prepare mango salsa and set it aside in the refrigerator.
Mix together sesame seeds, salt, and pepper and place on a plate.
Pat tuna dry and drizzle with avocado oil.
Press edges of tuna into sesame seed mixture. Use your hands to pack the seeds evenly and then set the tuna aside on a clean tray.
Heat a 10-inch cast-iron skillet over medium-high heat until it is very hot. Add 2 tablespoons of avocado oil to the skillet and coat the pan Once the oil is hot carefully lay the tuna in the skillet, pressing it down with a spatula.
Sear for approximately 60 seconds or until the side is golden brown.
Carefully flip and seared the second side for 60-90 seconds or until golden.
Sear the edges of the tuna by holding it upright with tongs.
Place the seared tuna on a cutting board and allow it to rest for 2-3 minutes. Using a sharp knife slice the tuna against the grain into approximately quarter-inch thick slices. Serve on white rice and topped with mango salsa.
1. Oil: Tuna needs to be seared quickly at high heat so use an oil with a high smoke point such as refined avocado oil which has a smoke point of about 520º. Avoid using extra virgin olive oil which only has a smoke point of 350º.2. Thawing: Tuna should not be thawed on the counter at room temperature. Tuna can be thawed in the refrigerator (8-12 hours) or using a cold water bath (~30 minutes). Frozen tuna steaks that are vacuum-sealed should be removed from the packaging prior to either thaw method. Thawing tuna in its vacuum seal can promote the growth of harmful bacteria. Tuna can be stored for up to 48 hours in the refrigerator after it has been thawed.3. Storage: Cooked tuna can be refrigerated for 3-4 days in an air-tight container.4. Nutritional Value: Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed. The nutritional value is only for the tuna and will vary based on the weight of the tuna. The nutritional value of the mango salsa can be found on the recipe card for that recipe. It does not include the nutrition for any substitutions.