Rinse the quinoa under cold water to remove any bitterness.
- In a medium saucepan, combine the quinoa and water (or vegetable broth). Bring to a boil, then reduce the heat to low and cover. Simmer for 15 minutes, or until the quinoa is cooked and the water is absorbed. Fluff the quinoa with a fork and let it cool to room temperature.
- In a large bowl, combine the cooled quinoa, diced cucumber, chopped red onion, and fresh parsley.
- In a small bowl, whisk together the olive oil, lemon juice, Dijon mustard, garlic powder, salt, and pepper until the dressing is smooth.
- Pour the dressing over the quinoa mixture and toss gently to combine.
- If desired, sprinkle the salad with crumbled feta cheese for added creaminess.
- Serve immediately or refrigerate for 15-20 minutes to let the flavors meld together.