Make the filling. Finely chop the shrimp and place half of it in a food processor with the cilantro, the whites of the scallions, the garlic, soy sauce, rice wine vinegar, toasted sesame oil, ginger, and lime juice. Pulse until the mixture becomes a paste. Transfer the shrimp paste to a mixing bowl and fold in the remaining chopped shrimp and the greens of the scallions.

Prep. Fill a pot with a few inches of water and set a steamer basket over it. Bring the water to a boil over medium-high heat while you assemble the shumai.

Assemble the shrimp shumai. Arrange several dumpling wrappers flat on a clean work surface and have a bowl of warm water nearby. Place about 1 tablespoon of the shrimp filling in the center of each wrapper. Dip your fingers in the warm water and wet the edges of the wrapper. Fold the edges of the wrapper around the filling, pressing the moist edges gently toward each other so they stick. Repeat with the remaining wrappers and filling.

Steam. Line the basket of the steamer with lettuce leaves and arrange the dumplings in the basket. Cover and steam for 4-6 minutes (6 minutes for larger dumplings) or until the shrimp turns pink. Do not crowd the steamer basket. Steam in batches if needed.

Serve. Transfer the dumplings to a serving plate and serve with a side of soy sauce or chili oil.