Cucumber and seaweed sunomono is a simplest side dish which you can make so quickly. Adding dashi stock to the dressing removes the sharp acidity of the vinegar and it is easier to eat.
Sunomono is like salad in the Western cuisine but usually served with smaller portion than salads. Su (酢) means vinegar in Japanese and sunomono translates to ‘food with vinegar’.
Just like with any other dressing, there are different types of sunomono dressing (please refer to Japanese Dressings for various dressing recipes). But my favourite is tosazu (土佐酢). While common Japanese vinegar dressings are made from rice wine vinegar, mirin/sugar and soy sauce, tosazu adds dashi stock to it, removing the harshness of the vinegar.
Tosazu is naturally milder than other sunomono dressings such as nihaizu (二杯酢, vinegar + soy sauce), sanbaizu (三杯酢, vinegar + soy sauce + sugar/mirin) because of the dashi. So you tend to use tosazu with delicate ingredients. My son does not like many sunomono because of the strong vinegar flavour. But if dressed in tosazu, like this dish of cucumber and seaweed, he enjoys it.
In this recipe, I used cucumber and wakame (ワカメ, seaweed) which is probably the best known combination of ingredients for sunomono. Sunomono ingredients can be just vegetables, just seafood or mixture of these.
Off the top of my head, the following are some of the classic sunomono ingredient combinations. Depending on the combination, vinegar dressings with different compositions will be used.
- Julienned white radish and carrots
- Sliced cooked octopus and cucumber
- Crab meat and cucumber
- Thinly sliced lotus root
- Sashimi yellow tail
- Wakame (seaweed) cucmber and shirasuboshi (dried tiny whitebate)
I used dried wakame seaweed in this recipe but if you can get fresh wakame, that would be the best. Nothing compares with the fresh version – a deeper dark green colour with a crunchier texture. Unfortunately, I cannot get fresh wakame in Australia so I try to get the best quality dried wakame.
Good quality dried wakame gives you a better colour when rehydrated. I tried cheap ones as well but naturally, the more expensive ones are closer to the fresh wakame, retaining a touch of deep green colour. The cheaper it gets, the browner the colour of the wakame gets when rehydrated.
Yumiko

The Prep Time does not include time to soak dried wake seaweed.
- 1 cup thinly sliced cucumber
- ½ tsp salt
- 2 tbsp dried cut wakame seaweed (Note 1)
- 2 tbsp dashi stock (Note 2)
- 1 tbsp soy sauce
- 1 tbsp mirin
- 2 tbsp rice wine vinegar
-
Soak dried wakame in a bowl filled with water for about 10-15 minutes until rehydrated. Drain water well and move to a mixing bowl. If the wakame is not cut into bite size pieces, you need to cut them into about 2cm / 1 inch length.
-
Sprinkle salt over the cucumber and massage in to soften the cucumber. Squeeze to remove excess water well. Add to the bowl and mix with wakame.
-
Combine vinegar marinade ingredients and mix well.
-
When ready to serve, add vinegar dressing to ingredients and mix well. Serve immediately (Note 3).
1. Wakame is different from nori seaweed so please do not get them mixed up. Nori seaweed is sold in a rectangular black sheet and is used for sushi rolls. You may find non-cut dried wakame. In this case, you just have to cut it into small pieces after you've rehydrated.
2. I used dashi seasoning to make dashi. Refer to the packet instructions for the ratio of powder and water. I used boiled water so that the powder dilutes easily, then cooled it down completely.
If you would like to make dashi from scratch, please refer to the link on the ingredient which includes vegetarian dashi.
3. If you leave the cucumber and wakame in the dressing too long before serving, it will lose the fresh colour of the ingredients. So only dress just before serving. You could serve the sunomono in a bowl to share or in small bowls as an individual serving.
Hi Yumiko! Thank you for all the recipes shown. I just cannot leave once I read on. They are so clear understanding and look great. I will try out your recipes sometimes next week when I am not so busy. Thank you so much.
Hi Rossi, you are most welcome. I hope you enjoy many of my recipes!