For the Quick Pickles
For the Marinade
For the Rolls
To make the pickles: Whisk together vinegar and sugar in a small bowl. Place cucumber, carrot, daikon in a jar or container. Pour in enough vinegar and sugar mixture to fully submerge vegetables. Cover and let stand for at least one hour, or transfer to refrigerator for up to a week.
To make the marinade: Whisk together fish sauce, water, sugar, garlic, and black pepper in a small bowl. Place shrimp in a resealable plastic bag and pour in marinade. Seal bag and place in refrigerator while preparing vermicelli and grill.
Bring a medium pot of water to a boil. Add in vermicelli and cook for 3 minutes. Drain in colander and run under cold water. Set aside.
Light one chimney full of charcoal. When all charcoal is lit and covered with gray ash, pour out and spread the coals evenly over entire surface of coal grate. Alternatively, set all the burners of a gas grill to high heat. Set cooking grate in place, cover grill and allow to preheat for 5 minutes. Clean and oil the grilling grate. Skewer shrimp and place on grill. Grill skewered shrimp over direct heat until shrimp are opaque and cooked through, about 2 minutes per side. Transfer shrimp to platter and remove from skewers.
Fill a large, shallow bowl with hot water. Place 1 spring roll wrapper in water and let soak until soft and pliable, about 15 seconds. Transfer wrapper to a work surface. Place 3 shrimp in center of wrapper and top with lettuce, vermicelli, pickles, a few mint leaves, and a few sprigs of cilantro. Fold bottom of wrapper over filling, fold over sides around filling, then roll wrapper shut. Repeat with remaining 7 wrappers. Serve immediately.
h/t Serious Eats.