Ume plum vinegar can be found in the Japanese or Asian section of many supermarkets and in natural food stores. You could substitute balsamic vinegar with some salt added.
2 c freshly cooked (basmati) rice
1 c grated red radish
1 T ume plum vinegar
2 red radishes, sliced
1. While the rice is cooking, combine the grated radish and the ume plum vinegar and set aside for up to 30 minutes.
2. Put rice in a serving bowl. Drain liquid from grated radishes. With a spoon, gently mix the grated radishes into the rice. Garnish with the sliced red radishes.