Prepare Sushi Rice. Cut Roasted Seaweed sheets in half (4 x 7 1/2″ or 10 x 19cm). Set aside.
Prepare Kanpyo. In a large bowl, wash Kanpyo in water. Drain water, and rub with salt very well. Rinse and soak in water for 10 minutes. Cook Kanpyo in boiling water for 10 minutes. Strain water. Then put Kanpyo, 3/4 cup water, Soy Sauce, Mirin, and sugar in a pot, and cook until the liquid is mostly gone. Let cool. Then cut Kanpyo into 8" long strips.
Put a sushi mat flat on your work surface with the bamboo slats left to right, so you can roll the mat away from you. Place a piece of seaweed on the sushi mat with one of the seaweed’s long sides close to the front edge of the sushi mat (the edge near you).
Spread about 1/4 cup Sushi Rice on the seaweed leaving a 1″ (2.5cm) space along the far edge of the seaweed. Place cooked Kanpyo strips on the middle of the rice. Holding the filling down, roll from the front end of the mat guiding with the sushi mat toward the other end. Tighten the rolls like roll cakes, pulling the mat to tighten. Make 4 rolls.