Preheat oven to 350 degrees. Unroll crescent dough; do not separate. Using lightly floured pizza roller, roll out dough on 12x15 baking sheet. Bake 12-15 minutes or until golden brown. Cool completely. Mix mayo, sugar, and vinegar. Chop broccoli and bacon. Cut a thin slice of onion into quarters; separate pieces. Spread mayo mixture over top of crust. Sprinkle with broccoli, bacon, onion, raisins, and sunflower seed kernels. Serve immediately or refrigerate.