First, in a pot filled with salted boiling water, cook the spaghetti until al dente and drain them well. Wash them with cold water and drain them well.
In a large mixing bowl, combine the cooked spaghetti with red bell pepper, green bell pepper, cucumber, zucchini, tomatoes, red onion, and black olives.
Whisk the Italian dressing, parmesan cheese, sesame seeds, paprika powder, celery seeds, and garlic powder in a smaller bowl.
Pour the dressing all over the pasta and veggies and toss until combined.
Chill well before serving.