Make this salad ahead of time. Combine all ingredients (except basil) and store up to two days before serving. Mix in the sliced fresh basil before serving.
Prepare orzo per package directions. Run cold water over cooked orzo in a strainer to cool and set aside.
In a large bowl, add red onion, asparagus, peppers, tomatoes and olives. Mix well.
Add vegetables into orzo, combine evenly. Pour dressing over salad ingredients, tossing to coat. Fold in basil right before serving.