Begin by preparing the marinade: in a small bowl, combine olive oil, lemon juice, minced garlic, and chopped fresh herbs.
Place the chicken breast in a shallow dish and pour the marinade over it, ensuring it is well coated. Allow it to marinate for at least 30 minutes in the refrigerator.
While the chicken marinates, rinse the quinoa under cold water. Cook the quinoa according to package directions, typically simmering in water for about 15 minutes until fluffy.
Preheat a grill pan or skillet over medium-high heat and cook the marinated chicken for about 6-7 minutes per side, or until fully cooked and juices run clear.
Prepare the fresh vegetables by halving the cherry tomatoes, dicing the cucumber, and lightly tossing with fresh spinach.
Slice the cooked chicken into strips or cubes and arrange over a bowl filled with quinoa.
Top the chicken and quinoa with the fresh vegetable mix, and drizzle any remaining marinade over the bowl for an extra burst of flavor.
Serve immediately and enjoy this wholesome, balanced meal.