Combine cucumber and onion slices in large bowl. Layer with salt and cover with ice cubes. Let stand 1 1/2 hours; drain and rinse.
Place remaining ingredients in large sauce pot and bring to a boil. Add drained cucumbers and onions and return to a boil.
Pack hot into hot jars, leaving 1/4 in. head space. Adjust caps. Process 10 min. in boiling water bath.