Preheat oven to 375°F (190°C). Split each pita round into two halves to make pockets, then cut each half into 6–8 strips or roughly 1" pieces. Put pita pieces on a rimmed baking sheet, toss with 1 tablespoon olive oil to coat, spread in a single layer, and sprinkle lightly with salt and optional 1/2 tsp sumac or wild oregano. Toast in the oven for 8–12 minutes, tossing once halfway, until golden and crisp. Remove and cool — they will crisp more as they cool.

Dressing

Whisk dressing

In a small bowl or jar combine 4 tbs extra-virgin olive oil, 3 tbs fresh lemon juice, 1 tbs red wine vinegar, 1 minced garlic clove, 1 tsp sumac, 1 tsp dried wild oregano, 3/4 tsp salt, and 1/2 tsp freshly ground black pepper. Whisk or shake vigorously until emulsified. Taste and adjust acidity or salt as desired (add more lemon or a pinch more salt).

Salad assembly

Prepare vegetables and herbs

While pita toasts and dressing rests, prepare the produce: tear 4 cups mixed salad greens into bite-sized pieces, dice 1 cup cucumber, thinly slice 6 radishes, cut 2 medium tomatoes into 1/2" pieces, and thinly slice 2 scallions. Roughly chop 1 cup parsley and 1/2 cup mint (if using). Halve and pit Kalamata olives (about 1 cup). Crumble 3 oz feta into small pieces.

Combine and toss

Place the torn greens into a large mixing bowl. Add cucumber, radishes, tomatoes, scallions, olives, parsley, and mint. Pour the dressing over the vegetables — start with about three-quarters of the dressing and toss gently to coat everything evenly. Taste and add more dressing if needed. Add crumbled feta and toss gently once to distribute without breaking it down completely.

Add pita crisps

Just before serving, add the cooled pita crisps to the salad and toss briefly to combine. Reserve a few crisps for garnish if you like to keep some extra crunch on top.

Finish and serve

Transfer salad to a serving bowl or plates. Sprinkle a final pinch of dried wild oregano or sumac over the top if desired. Serve immediately so pita stays crisp. Leftover dressing can be refrigerated up to 3 days; keep pita crisps separate to maintain crunch.