Poach shrimp and slice in half lengthwise. In a bowl, combine marinade ingredients, stirring until sugar is dissolved. Add shrimp to the marinade and let sit for a few hours, chilled.
To assemble the rolls, place rice paper wrappers in a bowl of warm water for 2 to 3 minutes until they are soft. Lay out hydrated wrappers on a damp paper towel. In the center of the wrapper, place 1 each of carrot, cucumber, and scallion. Add 2 pieces of shrimp and 2 mint leaves. Fold in sides of the wrapper. Roll wrapper. Serve with peanut dipping sauce.