I'm a South Jersey native. We have lots of Wawa convenience stores around here, and while I don't go to them often any longer, I used to go a lot. They have a deli section where you can order subs and what not. I was always a pretty big fan of their tuna salad subs. Something about the flavor of that tuna salad always drew me in, but I had no idea what they put into it to make it so tasty, until a few months ago...
I think it was some act of desperation to get my little guy to eat the tuna salad I'd prepared, that had me experimenting with its taste. I ended up adding quite a bit of Italian seasoning to the tuna salad (along with the regular amounts of mayo [~1 tbsp], mustard [~1 tsp], and pepper [to taste]). The end result was REALLY tasty and reminiscent of those Wawa tuna subs that I still order on occasion. The bonus was that my son ended up devouring the tuna salad!
Another trick I found to get my little guy to eat a tuna salad sandwich was to melt some american cheese over top of the tuna on the bread (a toaster oven comes in handy for this). He was in a cheese loving phase at that point so anything with cheese was a sure thing.
What do you put in your tuna salad to give it that extra oomph and appeal?