Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken breast on one side of the baking sheet and arrange the asparagus spears and cherry tomatoes on the other side.
Drizzle the lemon-herb marinade over the chicken and the vegetables, using a brush or clean hands to ensure everything is evenly coated.
Roast in the center of the oven for 18 to 22 minutes, or until the chicken is cooked through to an internal temperature of 165°F and the tomatoes have just begun to burst.
Transfer the chicken to a cutting board and let it rest for 5 minutes before slicing it into strips.
Fluff the warm cooked quinoa and place it in a shallow bowl, topping it with the roasted chicken, asparagus, and tomatoes.
Garnish the entire dish with freshly chopped parsley and an extra squeeze of lemon if desired.