Trim the Napa Cabbage (4) cores and cut each cabbage in half.
Make a 2-inch cut through the core of each half of the cabbage. You want the cabbage leaves to be loose but still attached to the core.
Soak the cabbages in water to get all leaves wet. Discard the water. Wear gloves and rub the Kosher Salt (1/2 cup) in between cabbage leaves by lifting up every leaf. Use more salt around the stems where the leaves are thicker.
Let the cabbages rest for 2 hours to get well salted. The liquid from the cabbages over once every 30 minutes.
After 2 hours, rinse the cabbages well under cold running water. Remove salt and dirt. By now the cabbages should be soft. Split the halves into quarters along the slits you cut in the first step. Drain the cabbages well. Set aside.
While the cabbages are salting, make the kimchi paste base. In a medium saucepan, combine Water (2 cup) and Sweet Glutinous Rice Flour (2 tablespoon). Mix well and let it cook over medium heat for about 10 minutes until the mixture is bubbly.
Add Brown Sugar (2 tablespoon) and cook for another minute, stirring constantly. Remove the base from heat, pour it into a large mixing bowl and let it cool completely.
Now, prepare the vegetables. Peel Daikon (2 cup) and Carrot (1 cup) and cut them into thin matchsticks. Set aside. Chop Scallion (10 stalk) and place them together with the daikon and carrots. Set aside.
Assemble the kimchi paste by adding Minced Garlic (1/2 clove), Minced Fresh Ginger (2 teaspoon) and chopped White Onion (1) in the base, followed by Fish Sauce (1/2 cup) and Crushed Red Pepper Flakes (1 1/2 cup). Mix the mixture well until it turns into a thin paste.
Now, add chopped daikon, carrots, and green onions. Mix again.
Time to make the kimchi. Wear gloves and press the cabbage quarters in the kimchi paste, one at a time, spreading some pastern each cabbage leaf. When the cabbage quarter is covered with the kimchi paste, lift it up and fold the leaves towards the core.
Place it into containers such as jars and inner pots of crockpots. Repeat this step until all cabbages are handled.
Cover the kimchi and let it sit in the room temperature for a day or two. It will start fermenting.
After a day or two, press the kimchi with a spoon, if you see bubbles from the top, it means your kimchi is fermented. The kimchi will continue fermenting as time goes on. So storing it in the fridge from this point on will slow down the fermentation process.
When ready, chop the kimchi and serve. Enjoy!