Wash the radishes and cut into thin slices or sticks. Peel and fillet the grapefruit, collecting the juice. Cut the chives into fine rolls. Put everything in a bowl. Add the grapefruit juice and balsamic vinegar. Season to taste with a little salt, pepper and cane sugar. Mix everything well and refrigerate until ready to eat.
Delicious as a side dish or as a refreshing snack.