Mash the beans with a fork and add in the tuna, flaking it really well with your fork.
Add the egg, mustard, and all of your seasonings. Stir really well to combine everything, then form into 12 cakes.
Heat 1 tablespoon of oil in a large skillet and cook half of your tuna cakes until golden on both sides, around 6-7 minutes in total (about 3 minutes per side). Repeat with the remaining 1 Tbsps oil and tuna cakes.
To assemble for meal prep divide the romaine and quinoa equally among your meal prep bowls.
Top equally with tuna cakes, red onion, yogurt, and lemon wedges.
Keep refrigerated for up to 3 days.
Enjoy!