Slice the cabbage in half and remove the bottom core and any damaged leaves. Chop the cabbage into bite-sized pieces, about 1 1/2-inches. Submerge in a large bowl of cold water to rinse. Drain the water and very gently squeeze the cabbage to help remove more of the remaining liquid.
Next, the salt needs to be applied to the cabbage. To do this, take a large empty bowl and place a single layer of cabbage at the bottom. Sprinkle some salt on that layer, and repeat layers of cabbage and salt until all cabbage and salt have been used. The goal is to coat all of the cabbage with all of the salt. When finished, let sit for 90 minutes, stirring the mixture very gently with your hands every 30 minutes.
In a medium saucepan, stir together water and sweet rice flour. Once combined, put on the range over medium heat. Continue stirring until the mixture starts to boil. Once it begins to bubble, add sugar and continue stirring for a few minutes until it becomes slightly translucent. Remove from heat, set aside, and allow to cool (it can be slightly warm when you use it, but not hot).
In a blender, add garlic, ginger, onion, and soy sauce. Blend until well mixed, about 1-2 minutes. In a large mixing bowl, add the mixture from the blender to the rice flour sauce and stir. Add the Korean red pepper flakes and stir to combine. Gently stir the carrots, green onion, daikon radish, and leeks into the paste and set aside.
When the cabbage has finished sitting for 90 minutes, add cold water to the cabbage bowl and move just the cabbage (and not the salty liquid) to a new bowl. Perform this rinse a total of 3 times and after the third time, taste a piece of the cabbage. It should be pleasantly salty. If it is still too salty, and you will know if it is, repeat the rinsing procedure until it is palatable. Drain the final rinsing liquid from the cabbage.
Add the cabbage to the hot pepper vegetable paste and gently mix with cooking grade gloves until the paste is well distributed with the cabbage. If you do not have cooking grade gloves, use a long spoon and mix very gently.
