Prepare the salad dressing, by whisking together the olive oil, red wine vinegar, lemon juice, and dried oregano. Add salt and pepper, to taste.
In a large mixing bowl, add your fluffed couscous, tomatoes, cucumber, feta cheese, sliced olives, and red onion and mix well, until just combined.
Pour the dressing over it and mix very well, until the dressing is fully incorporated into the salad. Serve immediately, or refrigerate.
TO STORE: Couscous salad should always be stored in the refrigerator. It not only retains extra flavor (like a stew or curry), but there is no chance of the feta cheese spoiling. Refrigerated salad will keep for up to 1 week.