Place the orange zest in a medium bowl with the orange juice, shallots, vinegar, water, honey, olive oil, salt, and pepper and whisk well. Dressing may be made 3 days in advance.
To assemble the salad
Place the cabbage, radicchio, red onions, radishes and beets to a large bowl. Whisk the dressing and pour over the salad. Toss well. Taste and add salt and pepper if needed, and serve. Sprinkle pomegranate seeds on top if desired.