Combine zucchini, 1/4 cup salt, onions and water. Let this soak for 3 hours. Then mix: vinegar, 1/2 tsp. salt, turmeric, mustard seed, celery seed, and sugar. Boil for 3 minutes. Add drained zucchini and onions, cook until clear -- about 20 minutes. Seal in sterilized jars. Makes 4 pints.