Prepare the Cabbage: Slice the Napa cabbage into quarters, remove the core, and cut into bite-sized pieces. Place in a large bowl and sprinkle with salt; toss to coat. Let sit for about 2 hours.
Rinse and Drain: Rinse the wilted cabbage under cold water and drain thoroughly.
Make the Kimchi Paste: In a blender, combine garlic, ginger, fish sauce, and gochugaru; blend until you achieve a thick paste.
Mix in Vegetables: Combine drained cabbage with chopped green onions and carrots (if using). Add kimchi paste and mix using gloved hands.
Pack into Jars: Transfer the mixture to clean glass jars, pressing down to remove air pockets while leaving space at the top.
Ferment: Leave jars at room temperature away from sunlight for 1-5 days until desired tanginess is achieved, then refrigerate.
