Day 1: Slice the bok choy—separating the leaves from the base and slicing lengthwise along the base into halves. Place the leaves and stem strips into a large glass bowl. Sprinkle the salt throughout layers of the leaves and rub it into the base portions. Place a small plate on top and weight the plate with a quart-size (or larger) jar of water. (Just make sure the jar or object you are weighting with is clean on the outside; the jar will eventually be sitting in the salt water.) Let the bowl sit at room temperature for 8–10 hours.
Day 2: Rinse the brined bok choy under cold water to remove any excess salt water, chop it into 1-inch pieces and place in a large bowl. Add the remaining ingredients and mix to incorporate. Place the kimuchi in a 2-quart jar or divide evenly between four pint jars or two quart jars.
Pour 1 cup of water, total, into the jar(s), cap loosely and let sit at room temperature for 3–5 days. When soured to personal preference, place the jar(s) in the refrigerator where the kimuchi will keep for up to three months.