Cook the whole wheat penne in boiling salted water according to package instructions until al dente, then drain and rinse with cold water to stop the cooking process.
Season the chicken breast with a pinch of salt and pepper, then grill or pan-sear over medium-high heat for 6-7 minutes per side until fully cooked.
Let the chicken rest for 5 minutes before slicing into bite-sized cubes.
In a small jar or bowl, whisk together the extra virgin olive oil, lemon juice, sea salt, black pepper, and dried oregano to create the dressing.
Halve the cherry tomatoes, dice the cucumber, and roughly chop the baby spinach and fresh parsley.
In a large mixing bowl, combine the cooled pasta, diced chicken, tomatoes, cucumber, and spinach.
Pour the lemon-herb dressing over the salad and toss thoroughly until every ingredient is well-coated.
Garnish with fresh parsley and serve immediately or refrigerate for 30 minutes to allow the flavors to develop.