1. Cook green beans in boiling water 1 minute. Drain and plunge beans into ice water; drain.
2. Combine rice vinegar and next 3 ingredients (through salt) in a medium saucepan; bring to a boil. Cook until sugar dissolves.
3. Combine beans, squash, and remaining ingredients in a large bowl. Pour hot vinegar mixture over squash mixture. Toss well. Cover and refrigerate 8 hours, stirring occasionally.
Note: Squash mixture can be evenly divided among 4 (1-pint) jars. Store in refrigerator up to 1 week.