Bluefin tuna or yellowfin sushi grade tuna (Ahi) can be used for this recipe.
Place tuna in the freezer for about 90 min to harden, then cut into cubes. Season with olive oil; chill. Cut avocado into dices, season with lime juice, salt, and cayenne to taste; chill. Slice out shallots and toss in flour and fry; transfer onto a baking tray lined with paper towel.
Place a pastry ring onto a plate, add a layer of avocado and fill up with tuna. Garnish with fried shallots, and remove pastry ring. Top with arugula sprouts, and some tamari sauce. Serve with potato chips, or toasted baguette. Enjoy!