Place all ingredients in a large bowl. Massage the ume vinegar into the vegetables. This is kind of a moderately gentle massage. Continue until the vegetables start turning limp and releasing a fair amount of liquid. If you massage for a minute or two and the vegetables still feel dry, add a little more ume vinegar.
Find an appropriate bowl and plate combination. The plate should cover the top of most of the salad without it's edges contacting the sides of the bowl when pressing. Add a weight on top of the plate, like a jar full of water or a large can.
Let sit for 1 to 2 hours.
Turn the bowl sideways while pressing on the plate to help the excess liquid drain out. Toss with a fork. Serve.