Add the cottage cheese, mayonnaise, Dijon, 2 tablespoons of vinegar, and seasonings to a small food processor or blender. Blend until completely smooth, scraping down the sides as needed. Transfer the sauce into a big bowl.

Cook the pasta according to the package directions. While the pasta cooks, you can move on to the other things.

Add both cans of tuna to the bowl with the sauce, making sure to add the juice. Break up any big chunks of tuna with a fork.

Rinse the peas under hot water, drain well, and add them to the bowl.

Rinse and drain the beans and add them to the bowl.

Chop the hard-boiled eggs and add them to the bowl.

Add the scallions and mix well.

Once the pasta is fully cooked, rinse it with cold water to stop the cooking and drain well. Add the pasta and gently stir everything together until well combined.

Taste and adjust the salt, pepper, and vinegar.