How to Make It
Combine sugar, chile, garlic, lime juice, cilantro, 1 cup of the pineapple juice, and ½ teaspoon of the salt in a blender, and process on high until completely smooth, about 2 minutes.
Transfer pineapple mixture to a saucepan, and simmer over medium-high 5 minutes. Whisk together cornstarch and remaining 2 tablespoons pineapple juice in a small bowl. Whisk cornstarch mixture into pineapple mixture in saucepan, and simmer 15 seconds. Transfer sauce to a serving bowl, and chill, uncovered, until cool, about 20 minutes.
Meanwhile, heat oil in a large stockpot over medium-high to 300°F.
Add plantain pieces to hot oil. Cook, stirring often, until plantains are slightly browned around the edges and floating, 6 to 7 minutes. Remove from oil, and drain on paper towels. Increase oil temperature to 350°F.
Using bottom of 1-cup measure or a smooth mallet, gently mash plantain pieces to a ¼-inch thickness, taking care not to break them. Carefully return plantains to hot oil, and fry until browned and crispy, 2 to 3 minutes. Transfer plantains to a medium bowl lined with paper towels. Stir together cumin, paprika, and remaining 1 teaspoon salt in a small bowl. Toss together plantains and desired amount of cumin mixture, and serve with sauce and lime wedges.