In a bowl, gently stir together the pineapple, avocado, red onion, jalapeño, cilantro, and lime. Salt to taste. Cover and refrigerate until ready to serve.
Place a grilled brat on a warm hot dog bun. Top generously with the pineapple avocado salsa. Repeat with all the remaining brats and salsa. Serve with Sriracha on the side.