Cook the pasta according to package instructions until al dente. Drain and rinse under cool water to stop the cooking process. Meanwhile, season the chicken breasts with salt, pepper, and a pinch of oregano. Grill or pan-sear the chicken until fully cooked and lightly charred. Allow it to rest before slicing into bite-sized pieces.

In a small bowl, whisk together olive oil, lemon juice, minced garlic, dried oregano, salt, and black pepper. This simple dressing forms the fresh Mediterranean base of the salad. Adjust seasoning to taste, adding extra lemon juice if desired.

In a large mixing bowl, combine the cooled pasta, grilled chicken pieces, cherry tomatoes, cucumber, red onion, and chopped basil. Pour the dressing over the mixture and toss gently until everything is evenly coated. The ingredients should glisten lightly without becoming soggy.

Sprinkle feta cheese over the top if using, and give the salad one final gentle toss. Refrigerate for at least 20 minutes before serving to allow the flavors to meld. Serve chilled or at room temperature for best taste.