Soak dried seaweed in water briefly, then rub and rinse thoroughly.

Cut the seaweed into bite-sized pieces.

Wash the cucumber with coarse salt or baking soda, scrape off the skin bumps with the back of a knife, and julienne it.

Thinly slice the onion and soak in water to remove its sharp taste.

Prepare 600ml of water in a bowl.

Add 1 tbsp salt, 4 tbsp sugar, and 6 tbsp vinegar to the water and stir until dissolved.

Add the julienned cucumber and onion to the bowl.

Add ice cubes and seaweed just before serving.