Preheat oven to 350 degrees.
To make the pita toasts, cut each pita bread pocket in half, then cut each half into 5 or 6 triangles. Repeat for the second pita pocket.
Line a sheet pan with parchment paper.
Tear each pita triangle in half where the bread connects.
Spread out the triangles on the sheet pan with the inside of the pita face up.
In a small bowl, combine the olive oil, salt, and ground sumac.
Use a pastry brush to brush each triangle with a little bit of the oil mixture.
Put sheet pan into the oven and bake for 10-12 minutes, or until the pita toasts are lightly browned and crisp. Set aside to cool.
To start the salad, slice each cherry tomato in half.
Cut cucumbers lengthwise into quarters, then slice into ½-inch chunks.
Peel onion, and chop finely.
Slice olives in half.
To make the dressing, whisk together red wine vinegar, olive oil, salt, and pepper.
Put the tomatoes, cucumbers, onions, and olives into a large bowl, then add half of the dressing.
Stir together, and add more dressing as needed.
Crumble feta cheese over the salad and stir again.
Serve with pita toasts.
