Step 1: Rinse 1 cup of quinoa under cold running water in a fine-mesh sieve for at least 30 seconds to remove saponin.
Step 2: In a medium saucepan, combine the rinsed quinoa with 2 cups of vegetable broth (or water) and a pinch of salt. Bring to a boil over medium-high heat.
Step 3: Once boiling, reduce the heat to low, cover the saucepan, and simmer for 15 minutes, or until all the liquid is absorbed and the quinoa is fluffy. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork and spread it out on a baking sheet to cool completely.
Step 4: While the quinoa cools, dice 1 large cucumber, 1 red bell pepper, and 1/2 a red onion into small, uniform pieces. Halve 1 cup of cherry tomatoes.
Step 5: Finely chop 1/2 cup fresh parsley and 1/4 cup fresh mint.
Step 6: In a small bowl, whisk together 1/4 cup extra virgin olive oil, 3 tablespoons fresh lemon juice, 1 clove minced garlic, 1/2 teaspoon dried oregano, 1/4 teaspoon salt, and 1/4 teaspoon black pepper until well combined.
Step 7: In a large mixing bowl, combine the cooled quinoa, diced cucumber, red bell pepper, red onion, cherry tomatoes, chopped parsley, and mint. Add 1/2 cup pitted Kalamata olives.
Step 8: Pour the lemon-herb dressing over the quinoa and vegetables. Toss gently to ensure everything is evenly coated. Crumble 1/2 cup feta cheese over the top and gently fold it in. Taste and adjust seasoning if needed.
Step 9: Cover the bowl and refrigerate for at least 30 minutes (or up to a few hours) to allow the flavors to meld. Serve chilled.