1. Cook the pasta: Bring a large pot of salted water to a rolling boil. Add the rotini pasta and cook according to package directions until al dente. This usually takes about 10-12 minutes. The pasta should be tender but still have a slight bite.

2. Drain and cool the pasta: Once cooked, drain the pasta thoroughly in a colander. Rinse it with cold water to stop the cooking process and cool it down quickly. This prevents the pasta from becoming mushy and helps keep the salad fresh. Let it drain well.

3. Prepare the vegetables: While the pasta is cooking and cooling, dice your English cucumber, halve the cherry tomatoes, thinly slice the red onion, and halve the Kalamata olives. Chop the fresh parsley. Aim for uniform sizes for an appealing presentation and even distribution of flavors.

4. Whisk the dressing: In a small bowl or jar, combine the extra virgin olive oil, red wine vinegar, fresh lemon juice, dried oregano, and garlic powder. Season with salt and black pepper to taste. Whisk vigorously or shake the jar until the dressing is well combined and slightly emulsified.

5. Combine ingredients: In a large mixing bowl, add the cooled pasta, diced cooked chicken, cherry tomatoes, cucumber, red onion, Kalamata olives, crumbled feta cheese, and chopped parsley.

6. Dress the salad: Pour the prepared dressing over the pasta and vegetable mixture. Toss gently but thoroughly to ensure all ingredients are evenly coated with the flavorful dressing.

7. Chill and serve: For best results, cover the bowl and refrigerate the pasta salad for at least 30 minutes to allow the flavors to meld. This chilling time is crucial for the dressing to fully infuse the ingredients. Serve chilled.