Place ingredients for dressing in a small bowl and whisk together until emulsified. Alternatively, place all ingredients in a mason jar, cover securely with lid and shake until well combined. The ingredients will separate after a few minutes, so shake or whisk again before using.
Assemble Korean Chicken Salad
In a large mixing bowl, place shredded ¼ head purple cabbage, julienned carrots, sliced apples, sliced cucumbers, sliced scallions, and shredded chicken.
Drizzle with HALF the dressing, then toss to combine until all of the ingredients are coated well with dressing. Taste and add more dressing if needed.
Garnish with additional toasted sesame seeds if using. Divide salad among serving bowls/plates.