Mix cucumber/zucchini and onions in a large dishpan. Add ice and cold water to cover veggies. Mix the salt in well. All the veggies and salt mixture to set for 4 hours. Line a colander with a clean cotton dish towel. Drain the veggies mixture, squeezing as much juice from it as you can. Set aside. Wash pint canning jars. Set aside to fill. Prepare a water bath canner half full of water. Place on burner over medium heat. In a large kettle, bring vinegar, water, spices, and sweeteners to a boil. Add cucumber and onions. Bring to a boil. Ladle into pint jars within 1/2 inch of the top. Wipe top of jars clean with a damp paper towel. Add lids and rings. Place jars into water-bath canner adding more water if needed to cover the jars by 1 inch. Bring to a gentle boil. Reduce heat slightly and simmer for 15 minutes. Turn off heat. Allow canner to set undisturbed for 3-5 minutes. Remove jars. Allow jars to cool for 12-24 hours. Remove rings and check for seals. Store in a cool dark place.