Rinse the quinoa thoroughly under cold water to remove any natural bitterness.
In a medium saucepan, combine the rinsed quinoa and water (or broth). Bring to a boil, then reduce the heat to low, cover, and simmer for 15 minutes or until the liquid is absorbed and the quinoa is fluffy.
Remove the saucepan from the heat and let the quinoa cool completely to room temperature.
In a small bowl, whisk together the olive oil, fresh lemon juice, dried oregano, salt, and black pepper to create the dressing.
In a large mixing bowl, combine the cooled quinoa, cherry tomatoes, cucumber, red onion, black olives, feta cheese, and fresh parsley.
Pour the dressing over the salad and toss well until all ingredients are evenly coated.
Serve immediately or refrigerate for at least 30 minutes to allow the flavors to meld.