Step 1

Pulse cabbage and 1/4 teaspoon salt in a food processor until finely chopped, 8 to 10 pulses. Place mixture on a clean towel; squeeze to remove as much liquid as possible. Place in a large bowl; stir in pork, garlic chives, shrimp, 1/2 cup scallions, 2 tablespoons soy sauce, oyster sauce, Shaoxing wine, cornstarch, sugar, garlic, ginger, sesame oil, pepper, and remaining 1/4 teaspoon salt until combined. Sauté a small amount of filling until fully cooked; taste and adjust seasoning as needed.

Step 2

Working with 1 wrapper at a time and keeping remaining wrappers covered with a kitchen towel, place 1 level tablespoon of filling in center of 1 wrapper; gently press filling into an oval shape. Lightly wet edge of wrapper with water using an index finger. Place wrapper in 1 hand; bring wrapper sides up around filling to make a taco shape. Create a simple scrunch pleat by pressing to seal edges, creating a crescent shape. Place dumpling on work surface; using both hands, scrunch sealed edges toward center, creating zig-zag pleats. Place pleated dumpling on a large rimmed baking sheet dusted with flour, and cover with a damp towel. Repeat process with remaining wrappers and filling.

Step 3

Heat a large non-stick pan over high. Working in 3 batches, add 2 tablespoons oil; swirl to coat pan. Add 12 dumplings, pleated sides up. Pour in 1/2 cup water to come halfway up sides of dumplings; cover and reduce heat to medium. Cook, undisturbed, until water is evaporated and bottoms of dumplings are golden brown and crispy (sizzling will subside, and dumplings will smell toasty), 12 to 14 minutes (17 to 20 minutes if cooking from frozen). Transfer cooked dumplings to a platter. Repeat with remaining oil, dumplings, and water, wiping pan clean between batches.

Step 4

While dumplings cook, stir together remaining 1/4 cup soy sauce, vinegar, remaining 2 tablespoons scallions, and chile-garlic sauce, if using, in a small bowl. Serve dumplings with sauce.