Combine rice vinegar, sugar, olive oil and black pepper in a medium bowl. Stir with a whisk.
Cut the 1/2 cucumber in half vertically, remove seeds and slice. Slice carrots and green onion. Finely chop bell pepper.
Add carrots, onion, red bell pepper, cucumber and Mrs. Dash to vinegar mixture; toss to coat.
Cover and chill 30 minutes.