To assemble to norimaki rolls, have handy a small bowl of water and a sushi mat. The mat allows you to make the rolls neatly and firmly, as the nori itself is very fragile. (If you have no sushi mat, use a strong paper towel that has been moistened ans squeezed dry). Place the mat or towel on a clean, dry surface and place the nori, shiny side down on top.
Place the assembled sheet of nori on the sushi mat with the extra margin of nori furthest away from you. Spread the teaspoon of umeboshi paste across the rice with your finger and then add a bit of sauerkraut, a carrot strip and a scallion leaf neatly in a row.
Pick up the edges of the mat and nori together and begin to roll, tucking firmly into the center while bending the mat slightly up, takinf care no to catch it in the roll. If you're using a paper towel, follow the same procedure; make sure, after rolling it up, to squeeze the middle of the cigarlike roll to avoid a bulge and make it even.