In a bowl stir together yogurt, sour cream, and vegetable soup mix. Squeeze excess liquid from spinach. Finely chop spinach. Stir spinach, jicama or water chestnuts, onion, and ground red pepper into yogurt mixture.
Cover and chill for 2 to 24 hours before serving. Serve with assorted vegetable dippers or assorted crackers. Makes 3 cups (forty-eight 1-tablespoon servings).