Layer salad ingredients in serving bowl. Mix dressing and parsley until blended. Drizzle over salad just before serving; mix lightly.
Salad and dressing can be prepared ahead of time. Refrigerate (separately) up to 2 days before tossing salad with dressing just before serving.
Cook the yellow and green beans together in boiling water in large saucepan. Drain beans, then rinse and pat dry before layering in serving bowl as a single layer of mixed beans.