Cut the omelet in half lengthwise.
Cut each half of the omelet in half again lengthwise, then cut each quarter piece in half again lengthwise. You will have eight even-sized logs.
Bring plenty of water to a boil in a large pot and add a little salt. Add the asparagus and cook for 1 minute. Drain and cool the spears under cold tap water. Drain them again and cut off the hard bottom ends.
Make shallow cuts on the belly side of the shrimp and bend the shrimp backward. Cook in salted boiling water for 2 to 3 minutes, or until cooked through. Drain the shrimp and cool them briefly under cold tap water. Drain them again and remove the shells. Toss the shrimp in a bowl with ¼ teaspoon salt, ¼ teaspoon sugar, and 2 teaspoons rice vinegar. Remove the shrimp from the bowl.
STEP 1: Setting Up
Line up all the filling ingredients—rolled omelet, asparagus, shrimp, sweet fish flakes, shiitake mushrooms, and kanpyo gourd—on a tray. Have at hand the sushi rice, nori, and a small bowl containing 1 cup of cold water with 2 tablespoons of rice vinegar or grain vinegar for moistening your hands, and a moistened clean cotton cloth, fukin, or synthetic or paper material (to wipe away excess water or any rice residue stuck to your hands). Have a well-sharpened knife at hand. Place a bamboo rolling mat on a working counter in front of you, with a short side facing you. If using a mat composed of bamboo strips that are flat on one side (and green-colored), be sure the flat side is faceup.
STEP 2: Spreading the Sushi Rice and Filling Ingredients and Rolling
Place a whole sheet of nori, shiny side down, on the bamboo rolling mat. Moisten your hands lightly with the vinegar water and pick up the sushi rice—about 1½ cups. Form the rice into a roughly egg-shaped ball and place it on the nori, 1 inch below the upper left edge. Spread the measured sushi rice evenly to the right (do this by supporting the rice ball with your right hand and pushing the rice with your left hand toward the right side of the nori) until you have made a band of rice along the nori, leaving 1 inch of the nori uncovered. Now, using all your fingers, spread the rice toward you, until you have covered the whole sheet of nori (except for the 1-inch strip at the top).
(If you are using wasabi paste or other sauce in the roll, smear the measured portion across the center of the sushi rice from left to right.)
Spread one-quarter of the fillings across the center of the sushi rice from left to right in the following order: sweet fish flakes, shiitake mushrooms, omelet, asparagus, shrimp, and kanpyo gourd. When finished, you will have covered the lower half of the nori with fillings. To roll, pull up the bamboo rolling mat near you and fold it over the fillings.
Pull back the edge of the bamboo rolling mat (so that you do not roll it into the sushi) and continue to roll tightly until the whole roll is complete. The 1 inch of exposed nori at the top will seal the roll. Now place the bamboo mat over the roll, holding the mat securely, to firm up the roll and square off the edges slightly. Remove the sushi from the bamboo rollingmat.
STEP 3: Cutting, Serving, and Storing
To cut the roll into eight pieces, first cut across the center with a sawing motion, not pushing down too hard, then cut each half-roll into quarters, wiping the blade of the knife with the moist cloth to remove the rice residue when necessary. Serve the rolls without a dipping sauce (as most of the fillings are fully flavored). You can prepare this roll half a day in advance.
When you store the rolls, wrap them (before or after slicing) in plastic wrap and put them in a sealable container. Keep the rolls in a cool, dry, dark place for short-term storage. Or for longer storage, refrigerate in the warmest part of the refrigerator, the vegetable bin. Remember that long refrigeration 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 can’t, always keep the rolls at about 40° to 45° F. Remove the refrigerated sushi from the refrigerator at least 20 minutes before serving.