Remove one of the outer leaves of the Napa cabbage and set aside.
Core the cabbage and cut into approximately 2-inch by 2-inch pieces.
Place cabbage pieces in a large bowl, sprinkle salt on the leaves, then toss to mix.
Set aside and allow to rest 30 minutes so the salt can pull moisture from the cabbage.
While the cabbage is resting, mince the green onion, peel and grate the carrots and daikon radish, and peel and mince the garlic and ginger.
After the 30 minutes are up, use a wooden pounder or clean hands to gently mash the cabbage leaves to further release juices.
Add the remaining vegetables, the fish sauce, and the red pepper flakes to the bowl of cabbage and mix.
Pack the kimchi mixture tightly into a sterilized quart-sized wide-mouth jar, filling to 1 inch below the top.
Fold the reserved outer leaf of the cabbage to fit on top of the kimchi mixture and press it down so that the brine covers the leaf.
Top with a glass fermenting weight to keep the mixture below the brine.
If you need more liquid to cover the cabbage, simply add a little filtered water to the top.
Seal the jar, place it out of direct light, and allow it to ferment for 3 to 21 days, occasionally opening the lid to release pressure. Add or remove brine as needed throughout fermentation if the level is not maintained at 1-inch below the lip of the jar. You should see occasional tiny bubbles rising along the inner sides of the jar as the veggies begin to ferment.
Refrigerate the finished kimchi after fermenting. If you're using a lid with an airlock, replace it with a regular lid before storing it.
Serve with beef, chicken, pork, seafood or alongside rice or other vegetables.