Bring a large pot of generously salted water to a boil. Add the pasta and cook until al dente, according to package instructions. Strain, rinse thoroughly with cold water to cool, shake off excess water, and transfer to a large serving bowl.
Meanwhile, prepare the pickles, cheese (if using), and onion. Add to the serving bowl with the pasta.
In medium bowl, whisk together the mayonnaise, pickle juice, dill, mustard, pepper, and cayenne (if using).
Pour the dressing over the salad as desired and toss to coat. It will seem a bit thin and watery, but the pasta will soak it up once it's refrigerated.
Refrigerate until ready to serve. This pasta salad is even better after it's been refrigerated for a day, so feel free to make it in advance!
Leftovers will keep for up to 4 days in the refrigerator.