Frozen Wild Tuna Tartar Cubes 454g

Preparation

• Rinse and drain rice in a fine-mesh sieve several times until water runs clear. Let sit 30 minutes.
• Combine rice and 2 cups water in a medium saucepan, season lightly with salt, and bring to a boil. Reduce heat, cover saucepan, and simmer until rice is tender, 18–22 minutes.
• Remove from heat and let sit 10 minutes. Fluff with a fork; keep warm.Meanwhile, soak hijiki in ½ cup cold water in a small bowl until rehydrated and softened, 30–35 minutes.
• Drain and mix in a clean small bowl with 1 Tbsp. mirin, 1 Tbsp. soy sauce, and ½ tsp. sesame seeds; let sit 5 minutes. Drain.Whisk vinegar, sugar, 1 ½ tsp. kosher salt, and 2 Tbsp. water in another small bowl.
• Toss cucumber with a pinch of salt in another bowl and squeeze to expel excess water. Add cucumber and jalapeño to brine and let sit at least 10 minutes and up to 1 hour to pickle.
• Combine citrus juice, white soy sauce, oil, remaining 2 Tbsp. mirin, and remaining 2 Tbsp. soy sauce in another small bowl; set ponzu aside. Whisk mayonnaise and chili paste in a final small bowl to combine; set spicy mayo aside.
• Just before serving, toss avocado into tuna mixture. Divide rice among bowls and top with tuna mixture, a dollop of spicy mayo, more sesame seeds, and some tobiko, if using.