Tuna paste is ridiculously easy to prepare and makes a great no cooking bento, cutting the preparation time to less than 20 minutes, including rice cooking time! Now, that's what I would call cooking on the go! You can also use the tuna paste for a great tasting onigiri or sushi.
This simple recipe requires only 3 ingredients: sliced pork loin (already mentioned minute steaks or easy steaks), shallots and teriyaki sauce. It's also one of the lazy recipes — part of it you can prepare evening before, and finish it quickly before serving or packing your bento box. Plus, marinating for a long time allows increased flavors to transfer easily across the meat!
There is literally no easier recipe in the world, that tastes so good and takes only few minutes to cook, including rice cooking time! I always do it during hot summer days, because it's a no-brainer.
You can serve it as a main dish with more fancy toppings, or as a side dish, but also it's a great addition to bento or a small snack!