Preheat oven, air fryer, or grill to 350 degrees.
Chop pitas into small squares and lightly brush with olive oil, season with salt and pepper.
Toast pita croutons 5-8 minutes, until crunchy. Remove and let cool.
In a large bowl, combine cucumbers, tomatoes, red onion, garlic, parsley, and mint. Add lettuce and radishes.
In a small bowl, whisk together lemon juice, olive oil, sumac, salt, and pepper.
Pour the dressing over the vegetables and toss well to combine.
Just before serving, add the toasted pita pieces and toss gently.
Serve immediately, garnished with extra sumac if desired.