In a mixing bowl, combine the white wine and white wine vinegar and season to taste with salt and pepper. Boil potatoes for about 20 minutes or until just tender. Drain, return to heat to let steam evaporate. Peel potatoes while still warm, slice them and add to the bowl. Mix with the wine and toss in olive oil, parsley and scallions; season to taste with salt and pepper and serve over greens.