I prefer pasta-salads without mayo- or creamy dressings. They keep better, should there be any leftovers, and also served outdoors on a hot day. So here goes:

Boil any amount of any pasta you have, we prefer ecliches or farfalles because of the shapes.
While the pasta is boiling, mix in a big bowl:
very finely chopped onion - preferably scallion, but any other kind will do,
crushed garlic - one or two sections
very finely sliced celery-stalks
chopped red pepper - canned, pickled or fresh
good vinaigre (red wine, tarragon or other)
olive oil
dash of worshestershiresauce
some very finely sliced chilipeppers, if you wish.

when pasta is cooked and drained, add hot to dressing. Toss and let cool.

When cold, add wat you like - corn, canned tuna or pieces of ham or chicken, maybee strips of salami, rings of leek, swiss cheese cubes, mussels, shrimp.
Anything you like, but not at the same time. Try combining shrimp, chicken and fresh mushrooms, or cheese and salami and more onion.

I don't think tomatoes should go into it, though. They can be used as a side dish. Well, maybe cherry-tomatoes.

Eat with your favorite dresing and crusty bread. (It's my daughters favorite summer lunch.)