1. Preheat oven to 500ºF. Line a rimmed baking sheet with foil and a second baking sheet with paper towels. In a small bowl, combine pineapple, lime juice, mint and 1 Tbsp. sugar. In another small bowl, stir together cinnamon and remaining sugar.
2. Put butter on baking sheet and place in oven for about 1 minute to melt. Place tortilla pieces on baking sheet; turn to coat with butter. Sprinkle with cinnamon sugar. Bake until golden, 3 to 5 minutes. Transfer chips to paper towel-lined sheet; let cool slightly before serving with salsa on the side.