Cook the pasta in a large pot in salted boiling water according to the package directions. Then drain and rinse with cold water. Transfer the pasta to a large bowl.
Add the diced onion, chopped pickles, shredded cheese, and sliced olives to the pasta.
In a small bowl, whisk together the mayo, mustard, pickle juice, garlic powder, onion powder, salt, and pepper until combined.
Pour the dressing over the pasta and gently mix everything together until evenly combined.
Top with extra pickles and olives if desired. Chill until ready to serve.
Notes
The pasta will soak up the sauce. Depending on how dry your area is, you may need to make more sauce and add it to your pasta. For instance, here in AZ I have to make 2 batches of sauce. I add the first batch right away and if I am preparing ahead of time I will save the second and add just before the party.