Split each pita in half horizontally; cut each half into 6 wedges. Arrange pita wedges, rough sides up, in a single layer on a large baking sheet. Lightly coat wedges with cooking spray; sprinkle with garlic salt.
Bake at 400 for 9 minutes or until golden brown and crisp. Cool completely.
Place yogurt and next 8 ingredients in a food processor; process until smooth.
Pour into a serving bowl; cover and chill at least 30 minutes.