1. To prepare dip, combine yogurt and goat cheese in a food processor; process until smooth. Add leek and artichoke; process until finely chopped, scraping sides. Add pecorino Romano, juice, pepper, and dash of salt; pulse until blended. Cover and chill 2 hours. Garnish with chives, if desired.
2. Preheat oven to 350°.
3. To prepare chips, cut each pita into 8 wedges. Arrange pita wedges in a single layer on a baking sheet; lightly coat with cooking spray. Sprinkle evenly with 1/2 teaspoon salt and garlic powder. Bake at 350° for 14 minutes or until toasted. Cool completely. Serve with dip.