Whisk together 2¼ cups flour and ½ tsp. kosher salt in a medium bowl. Add cold water and stir until combined. Knead dough on a lightly floured surface for 4 to 5 minutes or until a smooth elastic ball forms. Spray a large bowl with nonstick cooking spray; place dough in bowl and cover with plastic wrap sprayed with nonstick cooking spray. Let rise in a warm place for 20 minutes or until slightly puffy.

Meanwhile combine cabbage and 1 tsp. kosher salt in a fine-mesh strainer set over a large bowl. Let stand at room temperature for 15 minutes. Transfer cabbage to a clean dish towel; wrap and squeeze cabbage to removing excess liquid. Discard liquid.

For filling, place pork, drained cabbage, 3 Tbsp. cilantro, green onions, sesame oil, sherry vinegar, garlic paste, ginger paste, remaining 1 tsp. kosher salt and white pepper in a large bowl; stir for 2 to 3 minutes or until combined.

Line a large baking sheet with parchment paper. Lightly dust with flour; set aside.

Divide dough into 40 (½-oz.) pieces. On a lightly floured surface, roll each piece into a 3-in. round, lightly dusting surface as needed to keep dough from sticking.

For each dumpling, hold one dough round in the palm of your hand; use a spoon to place 1 Tbsp. pork filling in the center of dough. Working from one side, carefully seal by folding into a crescent shape; pinch edges together. Transfer dumplings to prepared baking sheet.

Heat 1 Tbsp. vegetable oil in a large nonstick skillet over medium heat. Add one-fourth of the dumplings in a single layer, bottom sides down. Cook for 1 to 2 minutes on each side or until golden brown on all sides. Repeat cooking remaining dumplings using remaining vegetable oil.

To serve, garnish dumplings with cilantro, if desired. Serve with sauce for dipping.