Remove the stems from the mini tomatoes and poke several holes using a toothpick. Cut off the stems of the shiso leaves and slice them thinly.

Boil water in a pot, add the mini tomatoes, and blanch for 10 seconds. Then transfer them to cold water, peel off the skins, and drain well.

Mix the seasoning ingredients (water and men tsuyu) in a bowl. Add the peeled mini tomatoes, cover with plastic wrap, and refrigerate for 1 hour.