Make the quinoa by adding the water, lemon juice and salt to the quinoa in a pot, boil in high flame till it starts bubbling, then lower the flame to simmer. Once all the water has evaporated, switch off the flame and keep the lid shut for 20 minutes to allow it to steam.

Marinate the tuna steaks in the orange juice, lemon juice, soy sauce, vinegar, salt, oil and ginger. Let it sit for at least half an hour in the juice.

Heating a frying pan on the highest flame till it is hot. Spray the pan with a little oil. Place the tuna steaks in the pan for about 2 minutes on each side to get a nice sear without overcooking the inside. Once the tuna is ready, set aside. Add the sauce from the marinade to the frying pan and cook for about one minutes while it thickens, stirring throughout.

Make the vinaigrette by whisking the vinegars with mustard and the spices.

Put the cooked sauce from the fish on the bottom of the plate. Add the cooked quinoa on top. Place slices of red onion on the quinoa. Slice the tuna very thin and fan on top of the quinoa. Top with the vinaigrette. Garnish with sesame seeds.