Let the rice cool down. Cut the cucumber lengthwise into 4 pieces.
Spread the rice on the nori seaweed, leaving 1/3 on the other side open. Sprinkle with a little salt, and put the mayonnaise, cucumber and crabstick on the near side.
Start rolling with both hands tightly. Keep rolling.
Cut and put in a bento box, and they're done!
If using half a sheet of nori, the rolls look like this.