Italian Tomato Cucumber Salad

4 tomatoes on the vine, cored and chopped

½ red onion, thinly sliced

½ seedless English cucumber, chopped

3 tablespoons extra-virgin olive oil, or more if needed

1 tablespoon chopped fresh oregano

salt and ground black pepper to taste

Mix tomatoes, red onion, cucumber, olive oil, oregano, salt, and black pepper together in a bowl; stir to coat. Let sit for 30 minutes to blend flavors.