If thats not your thing, consider making coconut milk smoothies. Some coconut milk, a banana, a cup of frozen berry mix (or whatever you want) and a tablespoon of coconut oil. Vary coconut milk until you get the consistency you want, don't use canned.
Why coconut milk over regular milk or almond milk?
I like to have a couple of pieces of toast with it as well, drizzled with olive oil.
Since it's not recommended to eat tuna every day (owing to concerns about mercury) try substituting with salmon and trout[2] several times per week, which are both low in mercury (relative to tuna).
[1] e.g. http://www.traderjoes.com/fearless-flyer/article/1655
[2] http://www.amazon.com/Bumble-Bee-Smoked-Salmon-Fillets/dp/B0...
[&] http://www.amazon.com/Bumble-Bee-Smoked-Skinless-Canola/dp/B...
Fast, healthy, and keeps you full till lunch (and beyond!)