Season the chicken breast evenly with the sea salt, black pepper, and half of the dried oregano.
Heat a non-stick skillet over medium-high heat and cook the chicken for 6 to 7 minutes per side until the internal temperature reaches 165 degrees Fahrenheit.
While the chicken is cooking, prepare the dressing by whisking together the extra virgin olive oil, fresh lemon juice, minced garlic, and the remaining dried oregano in a small bowl.
In a large mixing bowl, combine the cooked quinoa, baby spinach, diced cucumber, and halved cherry tomatoes.
Once the chicken is cooked, let it rest for 3 minutes before slicing it into bite-sized strips.
Add the sliced chicken to the quinoa and vegetable mixture, drizzle with the lemon-herb dressing, and toss thoroughly to combine.