In a large container, combine the cucumbers, onions and salt. Cover with crushed ice and mix well. Let stand for 3 hours. Drain; rinse and drain again., In a Dutch oven, combine the sugar, vinegar and seasonings; bring to a boil. Add cucumber mixture; return to a boil. Remove from the heat., Carefully ladle hot mixture into hot pint jars, leaving 1/2-in. headspace. Remove air bubbles and adjust headspace, if necessary, by adding hot mixture. Wipe rims. Center lids on jars; screw on bands until fingertip tight. Place jars into canner with simmering water, ensuring that they are completely covered with water. Bring to a boil; process for 15 minutes. Remove jars and cool.