Pat the chicken breast dry with a paper towel and season both sides with sea salt, black pepper, and dried oregano.
Heat a non-stick skillet over medium-high heat with half of the olive oil. Once hot, add the chicken and cook for 6-7 minutes per side until golden brown and cooked through.
While the chicken cooks, mince the garlic and finely chop the fresh parsley.
Halve the cherry tomatoes and dice the cucumber into small, bite-sized pieces.
In a medium mixing bowl, combine the cooked quinoa, cherry tomatoes, cucumber, parsley, and minced garlic.
Whisk together the remaining olive oil and lemon juice, then pour over the quinoa mixture and toss well to combine.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into thin strips.
Plate the quinoa salad and top with the sliced lemon-herb chicken.