Prepare your base: Ensure your quinoa (or other grain) is cooked and cooled. Fluff it with a fork.
Chop and assemble the veggies: In a large mixing bowl, combine the rinsed chickpeas, halved cherry tomatoes, diced cucumber, thinly sliced red onion, and halved Kalamata olives. Add the chopped fresh parsley and mint.
Make the dressing: In a small bowl or jar, whisk together the tahini, fresh lemon juice, olive oil, and minced garlic. Gradually add cold water, one tablespoon at a time, whisking continuously until the dressing is smooth and reaches your desired drizzling consistency. Season with salt and pepper to taste.
Combine and serve: Add the cooked quinoa to the large bowl with the vegetables. Pour about half of the lemon-tahini dressing over the mixture and gently toss to combine everything evenly. If using, gently fold in the crumbled feta cheese.
Plate your power bowls: Divide the mixture among serving bowls. Drizzle with the remaining dressing, or serve extra on the side. Garnish with a little extra fresh parsley if desired.