Meanwhile, heat to high heat a non-stick skillet. Once the skillet is hot, rub some olive oil over the yellowfin tuna and place the oiled side into the pan. Sear on high for 1 ½ to 2 minutes per side.
Remove from the skillet when done: they should be pink in the middle, sprinkle more olive oil over it, and gently squeeze lemon over each tuna.
Spread some of the spicy mango salsa in the middle of the plate and place the yellowfin tuna over it.
Storage You can easily store this fish and the mango salsa in the fridge.Make-Ahead: You can prepare the mango salsa the day before and let it rest in the refrigerator overnight. The flavors will continue to bind.Crushing the seeds the day before can be of help. Refrigerator: The tuna and mango salsa will last 3-4 days in the refrigerator in an airtight container. Freezer: Freeze the tuna for up to 3 months. While you can freeze the salsa, it may not retain its original texture.