Cook pasta in a large pot of salted water according to package directions.
Drain pasta and place in a large mixing bowl to cool.
Make dressing by whisking together yogurt, mayo, pickles, Djion, lemon juice, dill, salt and pepper in a medium bowl.
Add onion, celery, and peas to bowl with pasta. Flake tuna into mixing bowl with a fork.
Add dressing. Use a wooden spoon to combine. Taste and adjust seasoning (I add ¼ tsp more salt). The flavors will meld and get better as it sits in the fridge.
