Cut the Napa cabbage in half lengthwise, then chop into bite-sized pieces. Place in a large bowl and sprinkle with salt. Let it sit for about 1-2 hours to draw out excess moisture.
Rinse the cabbage under cold water to remove the salt, then drain well and pat dry with a clean towel.
In a separate bowl, mix together the Korean red chili pepper flakes, garlic, ginger, fish sauce, soy sauce, and sugar to create a paste.
Add the chopped green onions and julienned daikon radish to the paste and mix well.
Gently combine the cabbage with the paste mixture until the cabbage is well coated.
Pack the kimchi into a clean, airtight jar or container, pressing down firmly to remove any air bubbles.
Leave the kimchi to ferment at room temperature for 1-2 days, then refrigerate. The longer it sits, the more flavorful it will become.
Enjoy!