Make Karashimayo by stirring together the ¼ cup Japanese mayonnaise and 2 teaspoons Japanese hot mustard. Prepare some tezu by mixing a tablespoon of rice vinegar into a cup of water. Wrap your makisu (sushi mat) with plastic wrap.
¼ cup Japanese mayonnaise, 2 teaspoons Japanese hot mustard
Place one of the 5 nori sheets on your sushi mat with the long edge facing you. Wet your hands in the tezu and scoop up a ball from the 1 batch prepared sushi rice with one hand. Deposit this rice across the top edge of the nori in an even column.
5 nori sheets
Keep your hands wet and spread the rice down the nori towards you. Use a picking and placing action (you don't want to smear or mash the rice). Repeat as many times as needed to cover the nori with a thin, even layer of rice.
1 batch prepared sushi rice
Spread some of the 75 grams tobiko across the bottom half of the rice.
75 grams tobiko
Grab the two corners of nori closest to you, lift the sheet up and flip it over by moving the corners away from you (the corners you're not holding should now be closest to you).
Place two of the halves from 5 leaves lettuce just below the center of the nori and stagger a few wedges of 1 avocado on top.
5 leaves lettuce, 1 avocado
Place two pieces of shrimp tempura on top, with each tail sticking out of the opposite sides of the rice. Spread some Karashimayo on the tempura.
Lift the edge of the mat that's closest to you and roll it over the fillings until the edge of rice contacts the nori on the other side.
Press the mat evenly to compress the filling and set the shape of the roll.
Lift the edge of the mat and use it to roll the roll the rest of the way.
Wrap the roll in the makisu with its seam facing down. Use your hands to apply even pressure to the mat to set roll's shape.
Unwrap the roll and use a long, sharp, wet knife to slice both ends off of the tempura sushi.
Cut the roll in half. Line the two halves up and then cut these into thirds.