Wash and sterilize canning jars. Note: I have various sized jars but two 16 ounce-sized jars will work.
Wash and rinse the cucumbers very well in hot water.
On a large cutting board slice the cucumbers into ¼" slices using a chef knife or a crinkle-cut slicer.
Put the cucumbers in a large bowl and add the salt. Stir well to combine, then place in the refrigerator for one hour.
After an hour transfer the cucumbers to a colander and rinse well to remove the salt.
Put the cucumbers back into the bowl and add the onions.
In a medium-sized saucepan add the brine ingredients, both kinds of vinegar, both sugars, and the spices.
Cook the brining mixture over medium heat, stirring until the sugars melt, then let simmer for five minutes.
Pour the hot brine over the cucumbers and onions and let sit in the bowl for one hour.
Put the pickles and onion slices in the sterilized jars then pour the brine into the jars then press down on the pickles to release any air pockets. If necessary, pour more brine over the pickles. Leave ½" space at the top.
You will probably have some left over brine.
Clean around the top of the jars and the threads and seal tightly. Store in the refrigerator for up to three months.
These pickles are ready to eat the next day. They just need a good chilling.