Gather all fully prepared ingredients. Fill a 9-inch pie plate or deep skillet with about 1 ½ inches of very warm water (110°F to 120°F) to moisten rice paper sheets.

To assemble rolls, work with 1 rice paper sheet at a time. Slide rice paper sheet halfway into water, and gently rotate sheet using your hands to wet all sides, about 10 seconds total. (Do not leave rice paper standing in water.) Place rice paper sheet on work surface, and let stand until pliable and slightly tacky, 30 seconds to 1 minute.

Arrange 3 to 4 tablespoons lettuce in an about 5-inch-long strip across bottom third of rice paper sheet. Top with 2 cilantro leaves, 2 mint leaves, about 6 carrot matchsticks, and 8 to 10 cucumber matchsticks. Fold bottom of rice paper sheet up and over filling. (If paper is sticking to your fingers, dip fingertips into water and lightly re-moisten edges of sheet.)

Roll away from you once so that the bottom edge is just tucked under, keeping wrapper pressed tightly around filling.

Place 3 shrimp halves, cut sides up, in center of wrapper. Roll once more over shrimp; fold outer edges of sheet in toward center.

Continue rolling up, jelly roll–style, creating a small, tight roll. Transfer gỏi cuốn to a large plate. Repeat process with remaining ingredients, making sure to space finished rolls at least ¼ inch apart so they don’t stick together.