Slice the daikon crosswise as thin as possible.Use a mandolin slicer for better results.
Sprinkle 3 1/4 tablespoons of salt over the daikon. Mix well. Leave for 30 minutes. Put the daikon in a colander and wash with running water. Let the water drip.
Meanwhile, combine vinegar, 1/4 teaspoon salt, sugar and whole peppercorn. Mix well and then microwave for 30 seconds. Set aside.
Arrange the daikon and onion in a pickling jar. Pour-in the vinegar mixture.Cover the jar and refrigerate for 3 days.
Serve as side dish during lunch or dinner.
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