Spread olive oil over the tuna.
Put the sesame seeds in a container and dredge the tuna in sesame seeds until well covered.
Heat a pan with olive oil and sear the sesame-crusted tuna on all its sides (around 45 seconds).
Cut the tuna into around 0.8-inch thick slices.
Put the washed arugula and cress in a bowl, mix well, and season with lemon juice and olive oil. Add the blueberries and put them in a flat plate. Place the tuna pieces over the salads and serve.
