In a large bowl, combine the cooked quinoa, chickpeas, cherry tomatoes, cucumber, and baby spinach. Toss gently to mix all the ingredients evenly.
In a small bowl, whisk together the tahini, lemon juice, olive oil, salt, and pepper until smooth. If the dressing is too thick, add a tablespoon of water to reach your desired consistency.
Drizzle the tahini dressing over the quinoa mixture and toss to coat everything evenly.
Top the bowl with sliced avocado and crumbled feta cheese.
Serve immediately or chill in the refrigerator for 30 minutes to enhance the flavors.