Here's what Flickr member Jamieanne had to say:
Not your average potato salad! Boiled potatoes are cut in half, then fried, cut side down in a frying pan. The potatoes are then tossed with a dressing made from olive oil, finely chopped kalamata olives, garlic, and parsley, then watercress is stirred though. Best enjoyed warm, but tastes great cold too!
It looks like a great way to make something substantial and unique for your next picnic, all without the need for mayo or refrigeration!
Related: Classic Recipe: Smashed Potato Salad