Mix tomato sauce, mayo, and water. Pour over veggies. Sprinkle parmesan on the top.
You could add a vegan chicken-like meat substitute to the salad for some extra protein. This is what I did with this salad in the first place. (Boco has started to make their products vegan-friendly).
Note: I like my dressings pretty light so they're more of something that adds to the salad, rather than something that covers it up. You may want to add more dressing to this. (The dressing is very similar to French dressing.)