a sorta tuna mayo sandwich
An easy way with surplus Tonnato (Tuna) Sauce from the Vitello Tonnato:
Thinly slice a large Vine-Ripened Tomato and arrange on some Toasted Sourdough. Top with a sliced Hard-Boiled Egg, lashings of Tonnato Sauce and a few twists of Black Pepper.
A more refined Tuna Mayo Sandwich if you will.
gourmet traveller 
Oh that looks so gooooooood – you have no idea how hungry you’re making me! It’s like no tuna mayo sandwich I’ve ever had :)
Very refined indeed! Always nice to see two ways to use a left over sauce.