9 hours 40 minutes
Here's What You'll Need
sushi rice, rice vinegar, sugar, salt, grapeseed oil, sushi grade ahi tuna, scallions, jalapeño, black sesame seeds, kewpie mayo, sriracha, ponzu sauce
The day before, place rice in a strainer, run under cool water to rinse until water runs clear. Cook rice according to package or rice cooker instructions.
In a small sauce pan, combine rice vinegar, sugar, and salt. Bring to a simmer over medium-high heat, then whisk until dissolved. Set aside until rice is cooked.
Pour sushi vinegar on top of rice, directly in the pot it was cooked in. Use a spatula to gently toss the rice with vinegar, being careful not to squish the rice.
Transfer the rice to a small sheet pan. Press the rice into a flat even layer, about ½" tall. Cover with plastic wrap, then refrigerate overnight, or at least a few hours.
Cut the raw tuna into a small dice, then run a knife back and forth over it repeatedly until very finely chopped. Transfer tuna to a bowl. Add 3 scallions thinly sliced.
In a small bowl, combine Kewpie, Sriracha, and ponzu. Whisk well. Pour the spicy mayo on top of the tuna, then mix well to combine. Cover with plastic wrap, then refrigerate until needed.
Heat oil in a skillet. Using a knife, cut rice into rectangles about 2" x ¾". When oil is hot, add rice, making sure not to crowd the pan. Cook ~2 minutes per side. Transfer to a cooling rack. Repeat with remaining rice.
Place spicy tuna mixture on top of each crispy rice. Sprinkle with a pinch of sesame seeds, then top with a slice of jalapeño. Drizzle with a little additional spicy mayo, if desired, then serve immediately.