Real Mayo is the only way to go (rather than Miracle Whip).
When I have them, I love snipped greeen onions in a "normal" tuna salad.
I frequently don't mix a salad before eating tuna on a sandwich, (being lazy by nature). Insetad I 'll spread a bit of mayo on the bread, and pack on the tuna, veggies, and fresh ground pepper. Works best on a puffy bagel (blasphemy?), where the edges hold it all in.