Slice the napa cabbage and cut into quarters lengthwise. Then remove the cores. Cut each quarter into 2-inch wide strips.
Salt the napa cabbage and place in a large bowl. Then, massage the salt into the cabbage so it begins to soften. Add enough water to cover the cabbage and place a bowl or plate on top to weigh it down. Let it sit for 1-2 hours.
Rinse the napa cabbage under cold water a few times. Then drain it.
Combine garlic, ginger, sugar and 2 tbsp. of water in a small bowl and mix to form a paste. Mix in your Korean red pepper flakes.
Combine the paste with the cabbage, daikon, and scallions.
Use your hands (gloves optional) begin to work the paste into the veggies until coated.
Pack your kimchi into a glass jar and press down until liquid covers the veggies. Leave some space at the top (about one inch) and then tighten your jar lid on top.
Let it sit at room temperature for 2-5 days.
Check your kimchi once a day and press down on your veggies with a spoon to keep them submerged in the liquid. When the kimchi is to your liking, transfer to the fridge!