Heat oven to 450°F. In small bowl stir together all dip ingredients. Cover; refrigerate until ready to serve. Meanwhile, place frozen potatoes in 13x9 inch pan. Bake according to package directions. Sprinkle potatoes with garlic salt, onions, tomato and cheese. Continue baking until cheese is melted (2 to 3 minutes). Serve hot potato wedges with dip.
