For the Pickled Ginger Tartar Sauce: Combine all the ingredients in a small serving bowl and set aside.
For the Wasabi Guacamole: Add all the ingredients to a small serving bowl and mash together until smooth. Set aside.
For the Tempura Batter/Tuna: Whisk all ingredients together in a large bowl, but do not over mix. Keep well chilled in the refrigerator or over an ice bath until ready to use.
In a deep-fryer or stockpot, heat the oil to 350 to 375 degrees F. Cut the tuna into 2 portions. Dip each piece into the tempura batter, coating all of the sides. Lower into the deep-fryer and cook until the batter is crisp, but not overly browned, approximately 1 minute. Remove from the fryer to a cutting board and cut into 1/4 to 1/2-inch slices. Transfer the tuna to a serving platter and serve with the Pickled Ginger Tartar Sauce and the Wasabi Guacamole.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Matt DiGregory, owner of Standard Diner, in Albuquerque, NM.