I really like walnut oil for salad dressings, it imparts a much different flavor than olive oil. Here's the dressing I made recently:
2 Tbs Walnut Oil
1 Tbs Balsamic Vinegar
1 tsp Dijon Mustard
Black Pepper to taste
I also like to add other spices, like dried parsley/oregano/thyme to my vinaigrettes, and the walnut oil also works really well with rice vinegar and spices!
I also used it to make my almond butter, which tastes awesome