Place half of cucumber in a large glass bowl, and top with half of onion. Repeat procedure with remaining cucumber and onion.
Combine vinegar and remaining ingredients in a saucepan; stir well. Bring to a boil; cook 1 minute. Pour over cucumber mixture; let cool. Cover and marinate in refrigerator 4 days.
Note: Pickles can be stored in refrigerator for up to 1 month