Start by washing and drying the cucumbers. Dice them into bite-sized pieces and remove any seeds with a spoon to prevent excess moisture. Sprinkle a pinch of salt on the diced cucumbers and let them sit in a colander for about 10 minutes. Afterward, rinse and pat them dry with paper towels.

Flake the imitation crab meat into bite-sized pieces and add it to a large mixing bowl. Dice the avocados and toss them with a splash of lime juice to keep them from browning while brightening their flavor. Gently fold these ingredients together, taking care not to mash the avocados.

In a small bowl, combine the mayonnaise, rice vinegar, sesame oil, soy sauce, and sriracha. Whisk until the dressing is creamy and evenly mixed. Taste and adjust seasoning as necessary.

In the large bowl with the crab and avocado, add the prepared cucumbers. Drizzle the dressing over the salad mixture and gently toss everything together, being careful not to overmix.

Transfer the salad to a serving dish. Sprinkle toasted sesame seeds over the top and layer on nori strips if using. Refrigerate for at least 30 minutes before serving to allow flavors to meld.