Simply combine the vinegar, cider, and sugar in a plastic container, stir, and stick it in the fridge. Make enough to have a little pool in the bottom of the bowl once it is tossed with the veggies. Allow to rest 24 hours if at all possible. Everything Else:
Chop up the Bok Choy, Apples, Onions, and Pecans.
Just before serving toss the veggies and the vinaigrette.