Place the sliced cucumbers in a colander and toss with kosher salt. Let them sit for 10 minutes to draw out excess moisture.
While the cucumbers drain, whisk together rice vinegar, soy sauce, sesame oil, honey, and mayonnaise in a small bowl until smooth.
Rinse the cucumbers under cold water and pat them very dry with paper towels or a clean kitchen towel.
In a large mixing bowl, combine the dried cucumbers, diced avocado, shredded imitation crab, and green onions.
Pour the dressing over the salad and gently toss until everything is evenly coated.
Sprinkle with toasted sesame seeds and black pepper, then refrigerate for at least 15 minutes to let the flavors meld.
Taste and adjust seasoning if needed before serving chilled.