PREHEAT oven to 375°F. Separate dough into four rectangles. Press onto bottom and up sides of 15x10x1-inch baking pan to form crust, firmly pressing seams and perforations in dough together to seal. Bake 11 to 13 min. or until golden brown; cool.
MIX cream cheese, dressing, dill and onion salt until well blended. Spread onto crust; top with the remaining ingredients.
REFRIGERATE at least 1 hour before serving. Cut into 32 squares.