Rinse the short-grain sushi rice under cold water until the runoff is mostly clear. Drain and combine with 2 1/4 cups water in a rice cooker or heavy pot. Cook according to rice cooker instructions or bring to a boil, reduce to low, cover and simmer 15 minutes; remove from heat and rest 10 minutes, covered.

Season rice

While the rice cooks, warm rice vinegar, sugar and salt in a small saucepan or microwave just enough to dissolve sugar. Transfer cooked rice to a wide bowl, fan if available, and gently fold in the vinegar mixture with a wooden spatula to coat without smashing the grains. Let rice cool to slightly warm (room temperature) covered with a damp towel.

Lay out a bamboo mat and place a sheet of plastic wrap over it. Place a nori sheet shiny side down on the plastic. With wet hands, spread approximately 3/4 cup of sushi rice into a rectangle leaving a 1/2 inch top edge free. Pat rice thinly and evenly.

Tempura Shrimp & Filling

Prep shrimp

Pat shrimp dry, butterfly by cutting lengthwise (leave tail intact) or make a shallow slit to straighten. Season lightly with 1/2 tsp fine salt and 1/4 tsp black pepper. Dust shrimp with 1/4 cup flour to help batter adhere.

Make tempura batter

In a bowl, combine 1/4 cup flour and 1/4 cup cornstarch. Add 1 cup very cold sparkling water and stir briefly — batter should be slightly lumpy and cold. If batter thickens, add a tablespoon more sparkling water. Keep the batter chilled over ice if possible.

Fry shrimp

Heat 1 to 1 1/2 inches vegetable oil in a pot to 350°F (175°C). Working in batches, dip shrimp in batter, shake off excess, and fry until golden and crisp, about 2–3 minutes depending on size. Drain on a wire rack or paper towels. You need 3 shrimp per roll (for 4 rolls total).

Place a thin strip (about 1/2 inch) of cold cream cheese across the center of the rice-covered nori, then align three tempura shrimp tails pointing toward the edge nearest you so they will be visible when the roll is sliced.

Using the bamboo mat, roll tightly from the bottom edge to form a cylinder, applying gentle pressure to keep the shrimp and cream cheese snug. Seal the exposed nori edge with a little water. Repeat for remaining rolls.

Topping - Crab & Crunch

Prepare crab topping

Flake or shred the imitation or cooked crab into small pieces. If you prefer a creamier topping, fold in 1 teaspoon mayo; keep topping chilled until assembly.

Top rolls

Place each roll seam-side down. Using a sharp, wet knife, slice each roll into 8 pieces (wet the blade between cuts). Spoon a generous pinch (about 2 tablespoons total per roll) of shredded crab onto each piece, then top with a few thin jalapeño slices, a sprinkle of tempura flakes, and a pinch of sliced green onion if using.

Sauces & Finish

Make spicy mayo

In a small bowl combine 1/4 cup mayonnaise with 1 1/2 teaspoons sriracha. Taste and adjust heat to preference. Transfer to a squeeze bottle or small piping bag for cleaner application.

Drizzle about 1/2 tablespoon spicy mayo and 3/4 teaspoon eel sauce over each sushi piece. Serve immediately with soy sauce, pickled ginger and wasabi on the side.