Prepare the coleslaw dressing. In a medium bowl, combine the mayo, apple cider vinegar, Dijon mustard, maple syrup, celery seeds, sea salt, and several twists of freshly ground black pepper. Whisk thoroughly until the mixture is smooth and well-blended.

Assemble the coleslaw. In a large mixing bowl, toss together the shredded green cabbage, red cabbage, carrot peels, and chopped scallions. Drizzle the prepared dressing over the vegetable mixture, ensuring even coverage. Mix well until all the ingredients are coated with the dressing. Taste and adjust seasoning with additional salt and pepper if needed.