If using whole shrimp, peel and devein them, remove tails, then pat dry with paper towels. Roughly chop the shrimp into 1/4–1/2 inch pieces so they will be bite-sized and easy to eat in a hand roll.

Marinate

Combine soy sauce, sake, mirin and sesame oil in a bowl. Add the chopped shrimp, toss to coat, and let sit for 5–10 minutes (do not over-marinate or the shrimp will start to cure).

Cook shrimp

Heat neutral oil in a nonstick or cast-iron skillet over medium-high heat. Add the marinated shrimp in a single layer and cook, stirring occasionally, until opaque and just cooked through, about 2–3 minutes. Season with salt and black pepper. Remove from heat and let cool slightly.

Tobanji Aioli

In a small bowl, whisk together mayonnaise, toban djan, grated garlic, lemon juice, rice vinegar, sesame oil and sugar until smooth. Taste and adjust heat or acidity: add more toban djan for spice, more lemon for brightness. Season with kosher salt to taste. Chill in fridge while assembling hand rolls so flavors meld.

Hand Roll Assembly

Prepare rice and nori

If not already prepared, season freshly cooked sushi rice with rice vinegar seasoning (about 2 tbs per 2 cups cooked rice). Spread rice slightly warm so it is tacky but not hot. Keep nori sheets nearby, shiny side out.

Place a half-sheet or full nori sheet in your hand (for a cone shape, use a full sheet). With wet fingers, take about 1/2 cup of sushi rice and place it on one corner of the nori, shaping it into a small wedge that will form the base of the hand roll.

Add fillings: spoon about 1/4 cup of the cooked shrimp onto the rice. Drizzle 1–1.5 teaspoons of the tobanji aioli over the shrimp. Add a few cucumber matchsticks, 2–3 slices of avocado, and sprinkle about 1/2 teaspoon of sliced scallions on top.

Finish and serve: optionally drizzle a few drops (about 1/8–1/4 tsp) of toasted sesame oil over the filling and sprinkle with furikake or toasted sesame seeds. Roll the nori into a cone (hand roll) and serve immediately to keep nori crisp. Repeat to make 4 hand rolls.

Storage and serving note: Assemble just before serving. Any leftover aioli can be refrigerated in a sealed container for up to 5 days; leftover cooked shrimp for up to 2 days.