1. Place chopped cabbage leaves in a large bowl and pour the salt water over the cabbage leaves.
Mix well and allow salted cabbage to sit for at least four hours, until the cabbage is quite wilted down.
2. Place wilted cabbage in a colander and rinse very well to remove excess salt; transfer cabbage back to large bowl.
3. Combine the fine red chili flakes with a little warm water, and stir gently with a spoon to create a red chili paste. If you don't have the red chili flakes, you can use crushed red chili flakes instead. Use 1-2 tablespoons, depending on whether you want it very spicy, or insanely spicy. Mix whichever chili paste you have with your cabbage. If you are mixing with your hands, be sure to use rubber gloves.
4. Add minced garlic, minced ginger, green onions, and fish sauce, and mix well again.
5. Place yellow onion and apple in a blender with one cup of water. Blend well, and then add this natural sweetener to the cabbage.
6. Pour over the cabbage, and mix well so that all the ingredients are distributed evenly.
7. Spoon the cabbage into glass jar(s). Push down on cabbage leaves as they stack up inside the bottle.
8. Transfer any liquid that accumulated during the mixing process into the bottle as well - this liquid will become kimchi brine. Some liquid will also come out of the cabbage leaves as you press down on them as they are stacked in the bottle.
9. Be sure to leave about 2 inches of room at the top of the bottle before capping it tightly with a lid (if you don't leave enough room, you may end up with some liquid seeping out of your jars as it ferments). Allow your kim chi to sit at room temperature for 24 hours before transferring to the refrigerator for storage.