1. Set the tuna on a board as if it is a loaf of bread. Cut it in half through, with the knife parallel to the board. Place the two pieces on a plate.
2. Mash the garlic with a tsp each of salt and pepper. Mix in the soy sauce. Rub this mixture over the piece of tuna.
3. Place the radishes, cucumber, mint leaves and sesame seeds together in a large bowl and season with salt.Toss to combine then arrange on a serving plate.
4. Whisk avocado oil, sesame oil and juice of 1 lemon orlime together using a fork. Season with a good pinch of salt then spoon this over the salad.
5. Heat a large pan to medium-hot. Add a little vegetable oil to the pan and cook the 2 pieces of tuna for 1 minute on each side (but not the ends) until just browned all over, but pink inside. Rest tuna for 2 minutes before slicing.
6. Arrange sliced tuna on salad and add remaining lemon or lime halves to the plate before serving.

Tip: If you don’t like rare tuna, don’t buy tuna anyway and overcook it — the fish will be dry and stringy. Choose a different fish instead that you can successfully cook to medium. Try slices of kingfish or blue eye.Serving a bowl of steamed rice on the side would suit the extra hungry.