1. Preheat oven to 475°.
2. Combine potatoes, 1 teaspoon salt, pepper, and 1/2 tablespoon oil in bowl; toss to coat. Arrange potatoes in a single layer on baking sheet. Bake 25 minutes, turning after 15 minutes.
3. Place garlic on cutting board; sprinkle with a dash of salt, and crush with flat side of a large knife to make a paste. Place feta in bowl; mash with back of a spoon. Add yogurt, lemon juice, remaining oil, and garlic paste, stirring with a whisk.
4. Combine arugula, olives, parsley, and half of feta dressing in large bowl; toss to coat. Add potatoes; toss until arugula wilts, and cool 5 min-utes. Toss with remaining dressing and serve.