Core the napa cabbage and slice into thin, uniform strips about ¼-inch wide. Rinse the strips in cold water to remove any grit, then dry thoroughly with paper towels or a salad spinner—excess water will dilute your dressing. Place the crisp, dry cabbage in your largest mixing bowl.
Remove the tough core from the red cabbage and slice it even thinner than the napa—about ⅛-inch strips work best since red cabbage is denser. Rinse thoroughly and dry completely before adding to the bowl. The contrast in colors will make your salad visually stunning.
Trim the root ends and any wilted green parts from the scallions, then slice on a slight diagonal for an elegant presentation. This bias cut creates more surface area and a more refined look. Rinse briefly, pat dry, and add to your growing pile of vegetables.
Peel the carrots with a vegetable peeler, then continue peeling to create long, thin ribbons—this technique gives you delicate, paper-thin strips that integrate beautifully with the cabbage. If your peeler isn't sharp enough, julienne with a knife instead. Add the colorful carrot ribbons to the bowl.
Halve each Persian cucumber lengthwise, revealing the small seed cavity. Use a small spoon to gently scrape out the seeds—this prevents the salad from becoming watery. Slice the hollow halves into thin half-moons and add them to your bowl for a refreshing crunch.
Using two forks or clean hands, shred the cooled chicken into bite-sized pieces that will distribute evenly throughout the salad. The chicken should be in strips, not chunks—this ensures every bite has the perfect balance of protein and vegetables. Fold gently into the vegetable mixture.
In a high-speed blender, combine the sesame oil, rice vinegar, soy sauce, sugar, neutral oil, ginger, garlic, lemon juice, and a pinch of salt. Blend on high until completely smooth and emulsified—about 30 seconds. The dressing should be glossy and unified, with no visible pieces of ginger or garlic.
Pour about half the dressing over your salad—you can always add more, but you can't take it away. Toss vigorously with large spoons or clean hands, ensuring every piece is lightly coated. The vegetables should glisten but not swim in dressing.