Pat the chicken breast dry and season both sides evenly with the sea salt, black pepper, and dried oregano.
Heat the extra virgin olive oil in a medium skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 6 to 7 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden brown.
While the chicken cooks, halve the cherry tomatoes and dice the cucumber into bite-sized pieces.
In a small mixing bowl, whisk together the lemon juice and minced garlic to create a simple dressing.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into thin strips.
Assemble the bowl by placing the fresh baby spinach and cooked quinoa at the base.
Arrange the sliced chicken, tomatoes, and cucumber on top of the quinoa and spinach.
Drizzle the lemon-garlic dressing over the entire bowl and serve immediately.