Xoriatiki Salata Country Style Greek Salad

Name: Xoriatiki Salata (Country-Style Greek Salad)
Ingredients: 4 plum tomatoes, cored and cut into 8 wedges; 1 medium cucumber, halved lengthwise and cut crosswise into ½”-thick slices; 1⁄4 medium red onion, thinly sliced; 1⁄3 cup extra-virgin olive oil, plus more for drizzling; 1 1⁄2 tbsp. red wine vinegar; 1 tbsp. dried oregano, preferably Greek; Kosher salt and freshly ground black pepper, to taste; 3 oz. feta cheese, crumbled