Things You'll Need
Mortar and pestle, rolling pin or wooden spoon
Fresh tuna bears so little resemblance to what comes in cans or foil packets that they may as well be totally different species. Searing tuna creates a crisp crust that perfectly complements the lusciously tender pink fish in the middle. Adding a layer of crushed peppercorns provides a crackling texture and spicy bite that further enhances the tender silkiness of the fish. The keys to searing are a very hot pan and very short cooking time.
Rinse your tuna steaks under cool, running water to remove any stray scales or skin and to refresh the fish. Pat them thoroughly dry on all sides. Massage or brush sesame oil onto all sides of the tuna steaks. Mix a bit of mustard and ginger into the sesame oil before coating the fish for a more intense flavor.
Pour a small handful of mixed whole peppercorns into a mortar or onto a cutting board, being careful not to let them scatter. Crush the peppercorns with a pestle or rolling pin. Don't completely pulverize them, just break them up a bit.
Mix coarse salt in with the crushed peppercorns. You should not have nearly as much salt as you do pepper, but use your own judgment as to the exact amount. Kosher salt will do, but you can also use sea salt or something more exotic like Himalayan pink lava salt.
Place each tuna steak on the salt and peppercorns and press down lightly. Turn them over and repeat so that both sides are coated. Press the peppercorns and salt into the fish with your fingertips to help them stick.
Coat the bottom of a skillet with olive oil and heat it over high heat until the oil just starts to smoke. Place the crusted tuna steaks into the pan and cook them for no more than one to two minutes per side. Slice the tuna steaks across the grain or serve them whole.
Use coarse pepper if you do not have any whole peppercorns available to crush.
Blacken your peppercorn-crusted tuna steaks by leaving out the oil and searing them in a dry pan.
Never serve tuna raw in the center unless it is sushi-grade, fresh and comes from a reputable fishmonger.