Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente (about 9–10 minutes). Drain and rinse under cold water to stop cooking and cool the pasta. Toss lightly with a drizzle of olive oil to prevent sticking.

While pasta cooks, halve the cherry tomatoes, dice the cucumber and bell pepper, thinly slice the red onion, and slice the olives if needed. Cube the mozzarella or drain the mozzarella pearls.

In a small bowl or jar, whisk together olive oil, red wine vinegar, Dijon mustard, minced garlic, dried oregano, honey (if using), and a pinch of salt and pepper. Taste and adjust—you want a bright balance of tang and oil.

In a large mixing bowl, add the cooled spaghetti, vegetables, mozzarella, salami (if using), and parsley. Pour the dressing over the top and toss gently until everything is coated.

Cover and refrigerate at least 30 minutes to let flavors meld.

Just before serving, give the salad a quick toss, taste for seasoning, and sprinkle grated Parmesan if desired. If the salad seems dry after chilling, add a splash more olive oil or vinegar to brighten it.