Place the first 6 ingredients (through marjoram) in a food processor; pulse until coarsely ground.
Arrange 4 pita halves, rough sides up, on a baking sheet.
Brush with 2 tablespoons oil.
Spread 4 teaspoons pistachio mixture over each pita half.
Bake at 350 for 16 minutes, or until lightly browned and crisp. Repeat with remaining pita halves. Cool. Break each half into 4 pieces; serve with Feta-Peppercorn