Cucumber rolls are called kappamaki in Japan. It is one of the most popular sushi rolls and is easy to make, with just three ingredients–nori (dried seaweed), sushi rice, and cucumber. As there is no fish included, this roll is also perfect for vegetarians.
This recipe calls for Japanese cucumbers, which are long, slender and thin-skinned. They do not have seeds nor any bitter taste and are therefore easy to handle and a pleasure to eat. If you cannot find Japanese cucumbers, mini Persian or English cucumbers are good substitutes.