Trim both ends of cucumbers and slice into ¼ inch slices. Slice the onions into thin slices.
Layer ⅓ of the cucumbers and onions in a large bowl. Cover with ⅓ of the canning salt. Repeat two more times.
Top the final layer with ice cubes. Allow the bowl to sit for 1 ½ hours.
After approximately one hour, begin to prepare jars, lids, and rings by washing and keeping warm. Begin heating the water bath canner over medium high heat.
After the cucumbers and onions have rested, rinse with cold water and allow to drain.
Combine vinegar, sugar, and spices in a large non-reactive kettle.
Heat over a medium heat, slowly reaching a boil. Add drained pickles and onions.
Cook until the liquid returns to a boil. Remove from heat.
Ladle cucumbers, onions, and liquid into hot jars, leaving ½ inch headspace. (Be sure to equally distribute the pickling brine into each jar.)
Wipe jar rim with a damp, clean cloth. Put lids and rings on, tightening to fingertip tight.
Lower into canner, raising heat and bringing to a rolling boil.
Process for 15 min, adjusting for altitude (if over 1000 feet).
Remove the canner from heat, and allow jars to rest 5 min. Remove from the canner and allow to cool at least 12 hours before storing jars.