Mix plain flour and salt in a large bowl. Create a well in the center and gradually pour in boiling water, stirring with a fork until shaggy dough forms.

Knead the dough on a floured surface for about 10 minutes until smooth and elastic. Wrap in plastic wrap and let rest for at least 30 minutes.

In a mixing bowl, combine pork mince, spring onions, chives, coriander, garlic, ginger, light and dark soy sauces, sesame oil, rice wine vinegar, and egg. Mix thoroughly.

Divide rested dough into 8 pieces, roll into circles, and fill with 1-2 tablespoons of pork filling. Seal edges firmly.

Heat a non-stick skillet over medium-high heat with oil. Place dumplings and smash each gently with a spatula, frying until golden brown (about 2 minutes).

Add water to the skillet and cover immediately to steam filling (about 1 minute). Remove lid and allow water to evaporate.

Transfer cooked dumplings to a platter, top with toppings, and drizzle with chili oil before serving.