Line a baking sheet with parchment paper and preheat your oven to 350°.
In a medium bowl, toss the pita pieces with 1 tablespoon of the olive oil, 1 teaspoon of the sumac, and the salt and pepper. Toss to coat.
Spread the pita pieces on the lined baking sheet, and bake for 10 minutes, flipping them after 5 minutes. Keep an eye on them, as they can burn pretty quickly.
While the pitas are cooking, whisk together the remaining olive oil and sumac with the lemon juice, white wine vinegar and garlic in a small bowl.
In a large bowl, toss together the lettuce, tomato, cucumber, radishes, onion, and parsley. Add the dressing and tingly toss to combine. Top with the toasted pita pieces.