With the help of a potato peeler remove the peel of the tangerine and immerse it in 200 ml of extra virgin olive oil.
Leave in infusion for 24 hours. Wash the tuna slices, dry them and proceed with sanitization: deep-freeze the fish in Freddy with the function of shock freezing until it has reached -18°C to the heart (about 1 hour and 30 minutes), finally keep it in the freezer for at least 24 hours. In this way any bacteria present in raw tuna will be eliminated and will be ready to be seared in the pan.
Thaw the slices of tuna, salt and pepper slightly and sear in a pan with a little hot oil about 2 minutes per side. Slice the beets thinly. Serve the tuna in slices, laying it on a bed of beets and season with a drizzle of tangerine oil and some sesame seeds.