In a medium bowl, whisk together olive oil, lemon juice and zest, minced garlic, parsley, basil, oregano, salt, and pepper. Add the chicken breasts and turn them to coat thoroughly. Marinate for at least 15 minutes, or for richer flavor, up to 2 hours.

Rinse the quinoa under cold water to remove any bitterness. In a medium saucepan, combine the rinsed quinoa, water, and salt. Bring to a boil, then reduce the heat to low, cover, and simmer for 15 minutes. Remove from heat and let it stand for 5 minutes before fluffing with a fork, allowing it to cool slightly.

Preheat your grill or grill pan to medium-high heat. Grill the marinated chicken for 5 to 6 minutes on each side, or until fully cooked and juices run clear. Once done, remove from the heat and let it rest for 5 minutes before slicing.

In a small jar or bowl, whisk together olive oil, fresh lemon juice, Dijon mustard, honey (if using), salt, and pepper until well combined.

In a large bowl, arrange a bed of spinach or mixed greens. On top, layer the cooked quinoa, cherry tomatoes, cucumber, red onion, red bell pepper, and feta cheese if using. Add the sliced grilled chicken and drizzle the dressing over everything. Toss gently to combine or serve as individual bowls for a stunning presentation.