For the ponzu sauce: Combine the chicken stock, soy sauce, bonito flakes, lime juice, sweet rice wine, rice wine vinegar, minced garlic, black pepper and red pepper flakes in a pot and whisk until fully mixed together. Bring to a boil.
While that is heating up, mix together the cornstarch with 1/2 cup water. Once the ponzu sauce has come to a boil, pour in about 4 tablespoons of the cornstarch/water mixture. Stir the ponzu and let it come back to a boil. Judge thickness and add more if needed (you want it to glaze the tuna without the liquid running everywhere).
For the seaweed salad: Soak the wakame seaweed in water until it completely expands. Drain the water and mix the seaweed with the cucumber and bell pepper.
For the tuna: Heat the cooking oil in a pan. While the oil is heating, salt and pepper both sides of the tuna steak. Sear each side for 15 to 30 seconds for rare. Let rest, and then thinly slice.
For the fried wontons: Heat the oil in a pot over medium-high heat. Drop the chopped wontons in and fry until golden brown.
For the tortillas: Heat a nonstick skillet over medium-high heat. Heat the tortillas on each side until hot throughout.
To assemble: Divide the tuna between the hot tortillas. Take the seaweed salad and put on top of the tuna. Glaze the tuna and seaweed salad with the ponzu. Top with fried wontons.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.