Rinse the quinoa under cold water. In a medium saucepan, combine the rinsed quinoa with 2 cups of water or vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for about 15 minutes until fluffy. Let cool.

In a large bowl, combine halved cherry tomatoes, diced cucumber, diced bell pepper, finely chopped red onion, halved Kalamata olives, and chopped parsley.

Fluff the cooled quinoa with a fork and gently fold it into the bowl with the vegetables.

In a small bowl, whisk together olive oil, red wine vinegar, dried oregano, salt, and pepper. Pour over the quinoa and vegetable mixture and toss gently.

Fold in crumbled feta cheese. Chill in the refrigerator for at least 30 minutes before serving.