Cook the pasta according to package directions, adding a generous tablespoon of kosher salt to the water. Just before the noodles are done, add the broccoli to the pot. Boil for about 30 seconds, then drain everything into a large colander. Rinse well with cold water.
In a large mixing bowl, stir together the mayonnaise, vinegar, salt, pepper, and sugar. Add the cooked pasta and broccoli and stir well to coat.
Add the cucumber, red pepper, olives, and green onion and stir again. Taste and adjust seasonings if needed. Cover and refrigerate until ready to serve. Stir again just before serving.
Notes
This pasta salad is best served chilled. You can prepare it a few hours ahead of time.