Boil dried pasta under a rapid boil for approximately 10 minutes, or until pasta is just tender (al dente).
Chop up your vegetables and mix with olive oil, vinegar, and seasonings.
Other vegetables can be used in addition to or instead of the ones listed, though those are my favorites. Some other ideas include yellow or red bell pepper, zucchini, cucumber, fennel etc.
Once pasta is done drain and rinse with cool water.
Mix pasta with vegetables and mayonnaise if using. The pasta is great with or without.
Taste and adjust seasonings to your liking.
Add parsley and avocado on top if you like.
The longer this sits in the refrigerator the better it is, but it's great fresh as well.
It's great to make extra of this and leave out mayo and avocado. If I feel like eating my pasta with mayo or avocado, I just add it to my serving. This way the pasta will keep in the refrigerator for a few days no problem. It makes great left overs to bring to work for lunch.