Prep the Cabbage & Carrots: Quarter and core the Napa cabbage, then slice it as thinly as possible.
Using a swivel peeler, shave the carrots into long, paper-thin curls.
Julienne the Vegetables: Finely julienne the carrot curls, snow peas, bell peppers, green beans, and red onion. Carefully cut the fresh corn kernels from the cobs.
Combine the Slaw: In a large mixing bowl, add the sliced cabbage, carrot curls, all the julienned vegetables, and the fresh corn kernels.
Toss gently to mix.
Make the Vinaigrette: In a small bowl or jar, whisk together the sugar, cider vinegar, vegetable oil, and the pinch of celery seeds until the sugar is fully dissolved.
Dress and Marinate: Pour the vinaigrette over the vegetables.
Season generously with salt and black pepper, then toss everything together until well-coated. For the best flavor, allow the slaw to sit and marinate for at least 10 minutes before serving.