In a small bowl, mix olive oil, minced garlic, chopped fresh herbs, salt, and pepper to create the marinade.
Coat the chicken breast with the herb marinade and refrigerate for at least 30 minutes to allow the flavors to infuse.
Preheat a grill pan or skillet over medium heat. Grill the marinated chicken for about 6-7 minutes per side or until fully cooked. Once done, let rest for a few minutes before slicing.
Prepare the quinoa as per package instructions if not already cooked.
In a large bowl, combine the cooked quinoa, spinach, cherry tomatoes, and cucumber.
In a separate small bowl, whisk together tahini and fresh lemon juice to create a smooth drizzle. Adjust consistency with a splash of water if needed.
Top the quinoa salad with sliced grilled chicken, then drizzle the lemon tahini sauce evenly over the bowl.
Garnish with additional chopped herbs if desired and serve immediately.