Combine cabbage and salt in a large bowl. Add enough water to cover the cabbage. Keep the cabbage submerged with a plate or a sealable bag filled with water. Cover the bowl and let stand at room temperature overnight or up to 24 hours. Drain the cabbage, saving the brine. Rinse and squeeze the cabbage dry. Return to the bowl and add daikon and scallions.Advertisement
Place red pepper flakes, fish sauce, ginger, garlic and sugar in a mini food processor. Process until almost smooth. Transfer to the large bowl with the cabbage. Using a disposable food-safe glove, massage the vegetables and the red pepper mixture together until well coated. Pack into a 2-quart glass jar. Add enough of the reserved brine to just cover the vegetables. Screw on the lid. Place the jar on a rimmed baking sheet and let stand in a cool place. Make sure that the vegetables are always covered with brine. Taste after 3 to 5 days. The kimchi is ready when it tastes good to you. Reseal the jar and store in the refrigerator.
To make ahead: Refrigerate the finished kimchi for up to 3 weeks.