My Mom would always have a bowl of this made up in the summer for a quick light lunch. There is really no specific recipe or measurements - it's all to your individual taste.
Cook whatever type of pasta you like such as elbow macaroni, shells, penne etc. Drain and add any 'extras' you like, I chop up celery and radishes in small chunks. Add thawed frozen peas or if you're lucky to have your own fresh peas and a large can of drained tuna. ( I use water packed). Mix together a dressing of mayo, milk, vinegar and a pinch of sugar (I use Splenda) to suit your own taste whether it be tangy or a little sweet. Pour over the mixture of pasta and extras, mix together well. This time I added some chopped cashews, or use any nut you would like. The nuts can be mixed in at the same time or you can top your salad with them as you plate it. By mixing them in, you lose a little of the crunch...again all to your taste. Refrigerate until ready to use. To serve, place a serving of the salad on a bed of lettuce with crackers of your choice. Lately I've been buying the Wheat Thins 'flatbread' crackers, they are delicious and come in a few different flavors.
I love having this in the fridge when I run home at lunch time and want something light, fast and easy. It would stay fresh in the fridge for at least a week - but it never lasts that long! Enjoy and remember to just add your own favorite 'extras' .... olives, carrots, red onion are others I have used. You could also trade out the tuna for some cubed cooked chicken if desired.... something I haven't tried but sounds interesting!