Combine ingredients (except wrappers and sea blite) in a bowl, cover and refrigerate until needed.
For tamari and chilli dressing, add chilli flakes to a heatproof bowl. Heat oil in a small saucepan over high heat until surface is shimmering. Carefully pour hot oil over chilli, stir to combine and leave to cool (30 minutes). Strain oil through a fine sieve into a bowl. Add tamari, vinegar, sugar, Sichuan pepper, 2 tbsp water and a pinch of salt and whisk to combine.
Working with a wrapper at a time, place a rounded teaspoon of filling in the centre, dip a finger in water and dampen the edges, then gently lift one side of wrapper and fold wrapper in half over the filling creating a half-moon shape. Lightly press along edges to seal. Place dumpling on a tray lined with baking paper, cover with a tea towel, and repeat with remaining wrappers and filling.
Bring a large saucepan of water to the boil. Carefully add dumplings and boil until cooked and translucent (2½ minutes; to test if dumplings are ready, remove one and cut into it with a sharp knife to check that the filling is hot). Remove dumplings with a slotted spoon and drain.
Arrange dumplings on a platter, whisk tamari and chilli dressing well, then drizzle over dumplings to taste, top with sea blite and serve immediately.
