Tear or cut cabbage leaves from its body and rinse them with water. Sprinkle some salt over, more salt on the white stem parts. Let them sit for 3-4 hours turning the leaves other way once or twice during the soaking time. Rinse 2-3 times with water and put them in a colander to drain the excess water. Set aside.
Meanwhile, put 1 whole onion (including the outer skin but cleaned well), half of 1 large radish, and dried jujube slices in a pot, and pour 3 cups water. Bring to a gentle boil and simmer over low heat for 20-30 minutes. Collect the stock and reserve 1-1/2 cups.
To make the rice glue; combine the reserved stock with sweet rice flour. Bring to a gentle boil and cook until it thickens as you whisk continually, about 3-4 minutes. Set aside to cool down.
To make the kimchi filling; combine onion, apple, garlic, ginger and milk in a blender and puree until very smooth.
Combine the thinly sliced radish, Korean chili flakes, sugar, shrimp sauce, fish sauces, the rice glue and the onion milk puree in a mixing bowl. Add the chopped green onion and mix well. Set aside for 10 minutes.
To assemble kimchi; place a piece of cabbage leaf at a time in a shallow mixing bowl, spread a little bit of seasoning paste over the leaf thoroughly. Repeat the process with a few more leaves layering opposite direction. Stack the leaves in a kimchi container and complete the rest of the cabbage leaves with the seasoning paste.
At the end, pour 1/2-1 cup of water to a mixing bowl and swirl around to collect the residue of the seasoning paste. Pour over kimchi in a container.
Cover the kimchi with a piece of clean plastic and put something heavy (like 2 or 3 clean rocks) on top to seal out the air.
Let the kimchi to sit in a room temperature for 1-2 days first (depends on the temperature), and then continue to ferment in a refrigerator for 4-5 days or until it reaches to the fermentation level you desire.