Step 1: Shred the red cabbage by hand or in a food processor and transfer to a large bowl. Sprinkle the salt over the cabbage and toss thoroughly. Let rest for 40 minutes. Drain, rinse, and return to the bowl.
Step 2: Meanwhile, make the paste: Combine the water, rice flour, and sugar in a medium saucepan and bring to a simmer, stirring constantly, until the mixture thickens, 1 to 2 minutes. Allow to cool.
Step 3: To make the guts: Combine the red onions, carrots, green apples, chili flakes, fish sauce, garlic, and ginger in a large bowl with the red cabbage.
Step 4: Fold the guts into the cooled paste. Add the bacon and mix thoroughly. Wearing clean latex gloves, transfer the kimchi to a gallon glass jar or airtight plastic container with a tight-fitting lid. Let stand at room temperature for 24 hours, then refrigerate. The kimchi will be ready to eat in 4 or 5 days, and it will keep for another 2 weeks.