Toast your sourdough slices then drizzle a little oil on the bread. Layer on the strawberry slices, add a few tiny leaves of fresh basil and season with sea salt and black pepper.
Rinse and pat dry your tuna steaks.
Mix the olive oil and sesame oil together in a small bowl, sprinkle with sea salt. Add the wasabi or horseradish sauce, if you have it.
Pour the sesame seeds (a mix of black and white looks good or you can buy a special Japanese mix called furikake seasoning) into a plate. Brush the each tuna steak with the oil mixture then press the steaks down firmly in the seed mix, then turn it over so that the other side is covered with the sesame seeds too.
Prepare your barbecue and frying pan/grill pan; you want it very hot. Once hot, brush the pan with the rest of the oil and press the sesame covered tuna steaks into the pan. Do not cook for long if you like your tuna seared. You just want the edges to be cooked and the centre raw.
Once cooked to the degree that you like, remove from the pan and leave to rest for a few minutes…the tuna is easier to slice. Spread the slices on a bed of green salad leaves. Serve with the strawberry bruschetta.