1. Cook the pasta: Bring a large pot of salted water to a rolling boil. Add your chosen pasta and cook according to package directions until al dente. This usually takes about 8-10 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 is crucial for a cold pasta salad. Let it drain well.

3. Prepare the salmon: If using canned salmon, drain any liquid and flake it into bite-sized pieces in a large mixing bowl. If using leftover cooked salmon, flake it with a fork. Ensure there are no bones or skin if you prefer.

4. Chop the vegetables: Finely dice the red onion and celery. The smaller the dice, the better they will blend into the salad without overpowering it. Add them to the bowl with the salmon.

5. Whisk the dressing: In a separate small bowl, combine the mayonnaise, Greek yogurt (or sour cream), chopped fresh dill, and lemon juice. Whisk until the dressing is smooth and well combined.

6. Combine ingredients: Add the cooled, drained pasta to the bowl with the flaked salmon, red onion, and celery. Pour the creamy dill dressing over the pasta mixture.

7. Season and mix: Gently toss all the ingredients together until the pasta, salmon, and vegetables are evenly coated with the dressing. Season generously with salt and black pepper to taste. Start with a pinch and add more as needed.

8. Chill before serving: For the best flavor, cover the bowl and refrigerate the pasta salad for at least 30 minutes to allow the flavors to meld and the salad to chill thoroughly. This step is important for a truly refreshing cold pasta salad.