Pat the chicken breast dry with paper towels and season both sides evenly with sea salt, black pepper, and dried oregano.
Heat 0.5 tbsp of the olive oil in a medium skillet over medium-high heat. Once hot, sear the chicken for 6-7 minutes per side until golden brown and cooked through to an internal temperature of 165°F.
While the chicken is cooking, dice the cucumber, halve the cherry tomatoes, and finely mince the red onion and garlic.
In a large mixing bowl, combine the cooked quinoa, cucumber, cherry tomatoes, and red onion.
In a small jar or bowl, whisk together the remaining 0.5 tbsp of olive oil, fresh lemon juice, and minced garlic to create a bright vinaigrette.
Pour the dressing over the quinoa mixture, add the chopped fresh parsley, and toss thoroughly to combine.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into thin strips.
Place the quinoa salad in a bowl and top with the sliced lemon-herb chicken to serve.