FOR THE WASABI MAYO:
2 tablespoons wasabi powder
1 1/2 tablespoons water
1/2 cup mayonnaise
1 lemon (juiced)
FOR THE TUNA BURGERS:
1 1/4 pounds sushi grade tuna steaks (cut into 1/2-inch cubes)
4 scallions (finely sliced)
1 piece ginger (2-inches, peeled)
2 cloves garlic (peeled, finely chopped)
1 jalapeno (seeded, finely chopped)
2 tablespoons sesame oil
2 tablespoons mayonnaise
2 tablespoons olive oil
Kosher salt and freshly black ground pepper (to taste)
TO SERVE :
1/2 cup cilantro leaves (to garnish)
2 jalapenos (shaved, to garnish)
2 avocados (sliced, to garnish)
4 soft seeded buns (toasted)
For the Wasabi Mayo: In a large bowl, add the wasabi powder and water, and whisk to combine. Add the mayonnaise and lemon juice and whisk to combine. Refrigerate for at least 30 minutes prior to serving.
For the Tuna Burgers: In the bowl of a food processor, add tuna and pulse until finely ground. Spread tuna out on a parchment-lined baking sheet and place in the freezer for 15 minutes to completely chill. Also, place a medium mixing bowl, and the clean bowl and blade of a food processor in the freezer to chill.
Preheat a griddle pan over high heat.
In the bowl of the food processor, add the tuna, scallions, ginger, garlic, jalapeno, sesame oil, and mayonnaise, and pulse to combine. Into the chilled mixing bowl, add the tuna mixture, and form 4 patties.
Season each tuna patty with salt and pepper. Drizzle with olive oil. Place the tuna patties on the griddle pan and cook until charred and golden on each side, about 1-1/2 minutes per side.
To Serve: Add avocado slices to the bottom half of the bun. Top with the tuna patty, shaved jalapeno, and cilantro. Spread the wasabi mayo on the top bun and place on top.