In a bowl, add a handful of ice cubes and cold water to cover. With a small or medium sharp knife, cut green onion stalks into 3" lengths. Slice the green onion lengthwise into long thin strips, as thin as possible (see video). Place green onion slivers into ice water. Set aside while you continue with rest of recipe.
In a bowl, whisk together the soy sauce, sesame seeds, wasabi, sesame oil, salt and pepper. Add in the cooked shrimp, green onion and red pepper and toss to coat. Cut the avocados in half lengthwise. Remove the pit from the avocado and discard. Remove the avocado from the skin and place the avocado into a separate bowl. Add in the lime juice and use a fork to mash the avocado.
Spread avocado on each cracker. Top with a spoonful of the wasabi shrimp. Garnish with green onion curls.