Combine the salt, onion, and zucchini in a bowl and refrigerate over night.
Drain the moisture in the bowel through a strainer.
Rinse the mixture and make sure it is thoroughly drained before moving on to the next step.
In a separate bowl combine the celery seeds, black pepper, dry mustard, and nutmeg.
Heat over medium heat the spices, red bell pepper, apple cider vinegar, sugar, and zucchini mixture until it reaches a simmer - this takes about 25 minutes.
Fill the pint Mason jars with the mixture - leaving about a ¼ of an inch head room.
Place the heated lid and ring onto each jar.
Put the jars in the water bath - leaving about 2 inches of space in between each jar.
Cover the water bath canner with its lid and process for 25 minutes.
Remove the jars and place them carefully onto a towel (not touching) until you check them to make sure they have sealed and cooled before storing or consuming.