Step 1: Setting Up
Line up all the filling ingredients—crabmeat, cucumber, avocado, white sesame seeds, and Sriracha mayonnaise sauce—on a tray along with the sushi rice and half-sheets of nori, stacked up in a tin or in a closed sealable plastic bag. Have at hand a small bowl containing 1 cup of cold water with 2 tablespoons of rice vinegar or grain vinegar for moistening your hands and moistened clean cotton cloth, fukin, or synthetic or paper material (to wipe away excess water or any rice residue stuck to your hands). Open up your bamboo rolling mat and wrap it tightly in plastic wrap. Have a well-sharpened cutting knife at hand.
Step 2: Spreading the Sushi Rice and Filling Ingredients and Rolling
1. Place one half-sheet of nori, shiny side down, on the rolling mat with a long side facing you. Moisten your hands slightly with the vinegar water and pick up the sushi rice (about 7/8 cup), forming it into a roughly egg-shaped ball without squeezing.
2. Place the rice ball on the nori, ½ inch from the upper far left edge of the nori. Supporting the rice with your right hand, spread the rice evenly to the right, leaving ½ inch of the far end of the nori uncovered. Now, using all your fingers, spread the rice toward you, until you have covered the whole area (except for the ½ inch at the top).
3. Sprinkle the surface of the rice evenly with 1 tablespoon of white sesame seeds to form an outer coating for the roll.
4. Flip the rice-covered nori sheet over onto the rolling mat, lining up the bottom edge of the mat and the nori sheet evenly. The nori is now on top of the rice. Smear about 2 teaspoons of the Sriracha mayonnaise sauce across the nori from left to right, one-quarter of the way up the side nearer to you.
5. Arrange the crabmeat over the sauce-smeared area. Place two sticks of cucumber over the crabmeat and then two sticks of avocado on top of the cucumber sticks.
6. To roll, lift up the bamboo mat near you and fold it over the fillings. As you roll and the bamboo mat reaches to the surface of the nori, pull back the edge of the bamboo mat (so that you do not roll it into the sushi) and continue to roll tightly until the whole roll is completed, leaving the seam down the roll. Now place the bamboo mat over the roll, hold it securely to firm it up, and square off the edges slightly.
Step 3: Cutting, Serving, and Storing
It may be easier for you to cut the inside-out roll covered in plastic wrap. To cut the roll into six to eight equal pieces, first cut across the center with a sawing motion, not pushing down too hard, then cut each half-roll into thirds or quarters, wiping the blade of the knife with the moist cloth to remove the rice residue when necessary. Serve the rolls with additional Sriracha mayonnaise sauce or without a sauce.
You can prepare this roll several hours in advance. For short-term storage, wrap each uncut roll in plastic wrap, put it in a sealable container, and store it in a cool, dry, dark place. Or for longer-term storage, refrigerate it in the warmest part of the refrigerator, the vegetable bin. Remember that long refrigeration (even 1 hour) makes the plump, juicy rice dry and no longer pleasant. If you are using raw fish fillings, prepare the rolls just before serving. Or if you cannot, always keep the rolls at about 40° to 45° F.