Duck and Dogs on a Blanket

Name: Duck and Dogs on a Blanket
Ingredients: 2 jalapenos, halved and thinly sliced; 1 medium red onion, thinly sliced; 3/4 cup red wine vinegar; 1/4 cup sugar; 1 teaspoon celery seeds; 1 teaspoon mustard seeds; 1 teaspoon salt; 2 slices thick-cut bacon, cut into 1/4-inch dice; 1 or 2 legs duck confit; 2 large sweet onions, thinly sliced; 2 cloves garlic, minced; 1/4 cup balsamic vinegar; 1 teaspoon sugar; 1 sheet frozen puff pastry, thawed; Flour, for dusting; Whole-grain mustard, for spreading; 1/3 pound Gruyere, shredded; 2 hot dogs, split lengthwise and cut into fourths