INGREDIENTS
•
2 ounces (55g) red onion (1/4 medium 8-ounce onion), thinly sliced pole to pole
•
1/4 cup (60ml) red wine vinegar
•
12 ounces (340g) mixed ripe tomatoes, cut into slices and chunks (about 2 heaping cups when cut up)
•
12 ounces cucumber (340g; about 2 small cucumbers), peeled (or partially peeled or unpeeled, if you want some of the bitter skin); quartered lengthwise; and thinly sliced crosswise
•
1/4 cup pitted Kalamata or other briny black olives (about 1 1/2 ounces; 40g), see note
•
1/2 cup (120ml) extra-virgin olive oil, plus more for drizzling
•
Kosher or sea salt
•
2 big pinches dried Greek or Mediterranean oregano, divided
•
4 ounces (115g) feta cheese, preferably cut into slabs