Season the chicken breast with half of the sea salt, black pepper, and dried oregano.
Heat a skillet over medium heat with one teaspoon of the olive oil and sear the chicken until golden and cooked through, about 6 minutes per side.
While the chicken cooks, whisk together the remaining olive oil, lemon juice, lemon zest, minced garlic, and the rest of the salt, pepper, and oregano in a small bowl.
In a large mixing bowl, combine the cooked quinoa, diced cucumber, halved cherry tomatoes, and chopped fresh parsley.
Slice the cooked chicken into bite-sized strips or cubes once it has rested for a few minutes.
Pour the lemon-herb dressing over the quinoa mixture and toss well to ensure every grain is coated.
Top the salad with the sliced chicken and serve immediately or store in the fridge for a cold lunch option.