Bring a large pot of generously salted water to a rolling boil over high heat. Add pasta and cook according to package directions until al dente, usually 8-10 minutes. Test a piece before draining – it should have slight resistance when bitten.
While pasta cooks, prepare your fresh ingredients: peel and dice cucumber into bite-sized pieces, finely dice red onion (tip: soak diced onion in ice water for 5 minutes to reduce sharpness), and roughly chop fresh spinach into manageable pieces.
Once pasta reaches al dente perfection, drain thoroughly in a colander and rinse immediately under cold running water. Toss gently while rinsing to cool pasta completely and remove excess starch. Allow pasta to drain for at least 5 minutes, shaking the colander occasionally to release trapped water.
In a spacious mixing bowl, combine cooled pasta, cubed salami, diced cucumber, red onion, chopped spinach, mozzarella pearls, and sun-dried tomatoes.
Pour Italian dressing over the ingredients and sprinkle with freshly grated Parmesan cheese. Add salt and pepper.
Using large serving utensils or clean hands, gently fold all ingredients until everything is evenly coated with dressing. Be careful not to break the pasta or crush the mozzarella balls.
Taste and adjust seasoning as needed, adding more salt, pepper, or a splash of extra dressing if desired.
For best flavor development, cover and refrigerate for at least 30 minutes before serving, though it can be enjoyed immediately if you're short on time.
Before serving, give the salad a quick toss to redistribute the dressing that may have settled at the bottom of the bowl.