Begin by finely chopping the prawns or pulsing them in a food processor until minced but not puréed. In a bowl, combine the minced prawns with chopped water chestnuts, spring onions, coriander, ginger, garlic, egg white, and sea salt. Mix until the filling becomes sticky.

Take a gyoza wrapper and place about a tablespoon of the prawn filling in the center. Moisten the edges of the wrapper with a little water to help seal it. Carefully fold and pinch the edges tightly to create a seal.

In a bowl, whisk together the soy sauce, Chiankiang black vinegar, chili oil, sugar, and minced garlic until combined. Taste and adjust seasoning if necessary.

Bring water to a gentle simmer in a large pot. Carefully add the assembled dumplings, cooking for about 5-6 minutes or until they float and the filling is cooked through.

Transfer the cooked dumplings to serving bowls, drizzle with red oil sauce, and garnish with sliced spring onions before serving.