The crisp, herby potatoes also taste great on their own, and the Kalamata olive vinaigrette is wonderful on other things too. I love it tossed with cucumbers and tomatoes. To make this a more substantial meal, simply add some leftover grilled chicken or steak.
No arugula? Make it with romaine lettuce instead. My favorite variety of romaine is an easy to grow heirloom called Parris Island Cos, which is crisp, tasty, and amazingly heat tolerant.