Soak seaweed in water for 20 minutes. In the mean time, grate/mince ginger and scallion.
Thinly slice cucumber and avocado into long thin strip.
When seaweed are re-hydrating, rinse and thinly slice them.
In a bowl or container, add sliced seaweed and the rest of the salad ingredients. Stir well to mix them all.
Place a sheet of nori on top of bamboo mat with grainy side up.
Spread sushi rice evenly atop nori, leaving about an inch at the very end.
Take half the seaweed salad and arrange onto rice. Then place kani, cucumber and avocado slices.
Lift, tuck and roll into sushi roll. For more detail on rolling maki sushi, go here. Repeat above steps for second roll.
Cut sushi roll and serve with pickle ginger and some ponzu or soy sauce.