Boil the pasta by filling a large pot with water, adding salt, and bringing to a boil. Cook spaghetti according to package instructions until al dente, about 8-10 minutes.

Drain spaghetti in a colander and rinse under cold running water for about 30 seconds to halt cooking and cool it down.

Chop fresh vegetables: halve cherry tomatoes, dice cucumber, chop green and red bell peppers, and red onion.

In a mixing bowl, fold the cooled spaghetti into the chopped vegetables.

Add black olives (if using) and drizzle Italian dressing over the mixture, ensuring even coating.

Toss everything together with tongs to make sure every piece is coated in dressing.

Season with salt and pepper to taste. Garnish with Parmesan cheese if desired.

Cover and chill in the refrigerator for at least one hour before serving to allow flavors to meld.