Combine the cucumber and tomato in a bowl. Scoop out the cut avocado and add it to the bowl. Set aside.
To make the dressing, combine the red wine vinegar, garlic, oregano, and parsley in a small bowl. While whisking, slowly add the olive oil and continue whisking until emulsified. Season with sea salt and pepper to taste.
To serve, combine 1/3-1/2 of the dressing with the chopped vegetables. Enough dressing to coat. Taste. Add more cracked pepper and sea salt if necessary. Stir to combine and serve.