Break the spaghetti in half and drop into a large pot of boiling salted water; cook until al dente, about 6-8 minutes. Drain and rinse under cool water.
Meanwhile, place the sliced olives, chopped tomatoes, green bell peppers, onions, cucumber and salami in a large bowl. Add the cold pasta and pour half of the salad dressing over the top; toss to coat. Add more dressing, if needed.
Chill for several hours. Just before serving, add more dressing, if desired.
Cook's Notes: Some fresh cubed mozzarella cheese would be a great addition to this salad.