Total calories (approx): 520 (how calories are calculated) 
Time needed: 20-25 minutes in the morning if making from scratch; much less if using pre-made/pre-frozen components
Type: Bread-free, vegan
I’ve been thinking a bit about healthy bentos that you could make with the minimal equipment available in a college dorm room . This is one that could be made if you have a rice cooker, microwave and plug-in grill device like the George Foreman grill. It features a rice burger: two grilled or panfried rice patties with a Mediterranean flavored green vegan burger  that’s been glazed with some ketchup (you could also use barbeque sauce), plus a few leaves of arugula, in between. I’ve wrapped it up in kitchen parchment paper in the bento box, but here’s how it looks:
The kitchen parchment paper is really helpful when you are ready to eat the burger, since it keeps the fillings from dripping all over you. Here I am just about to take a bite:
I’ve just thrown in some cherry tomatoes and berries in the side. The burger itself has a lot of greens in it, so I’m happy that this lunch has enough vegetables, but you could add some carrot sticks and so on for even more.
The rice patties and the vegan burger can both be cooked in the grill (blanch the greens in boiling water). Both can be made and frozen, and defrosted in the morning for quick assembly! If the vegan burger is too much work to make, substitute a readymade vegan burger or cutlet instead.
If you go to Japan, you will encounter a fast food chain called MOS Burger. Their speciality is something called a MOS rice burger - a warm sandwich made of two pressed rice patties with fillings. They are a tasty alternative to a regular bun burger, especially if you are gluten-intolerant. Plus you can put a whole more more filling in between the patties than in an onigiri.
Making rice burger patties is even easier than making onigiri. All you need to do is to press a round of rice about 1/2 inch / 1cm thick firmly, using plastic wrap. (The rice should be Japanese-style medium grain rice or similar, the same as you would use to make onigiri (rice balls), or it will not stick together properly; long-grains rices like jasmine rice, basmati rice, Uncle Ben’s Carolina Rice, etc. will not work without a binding agent. In other words, just think of the burger patties as flat onigiri. See the exhaustive Onigiri FAQ page .)
Then, cook the patties on each side in a lightly oiled frying pan or grill - I use olive oil, or sesame oil for additional flavor - until a light golden brown. (If you are fat-paranoid, use a non-stick spray on a non-stick pan.) The patties are crispy on the outside and soft on the inside, and a great match for all kinds of fillings. Here’s another one I made some time ago for a warm late-night snack - cheese, a couple of slices of salami, and a thin large slice of tomato, all pressed together until the cheese melted. Delicious!
Ahead-of-time note: The uncooked patties can be frozen, well wrapped in cling film. They should be fine for a month or so (beyond that and like all cooked and frozen rice, it may start to get freezer burn). Defrost them in the microwave or overnight in the refrigerator, then cook in the frying pan.
And coincidentally, Bentoist has a rice burger bento  using a chicken tsukune burger  as the filling, which looks great! One of MOS Burger’s popular rice burgers is a all-veggie kinpira burger  - you can sort of replicate it by using carrot kinpira  as the filling.
The one drawback of rice burgers for me is that you need to use quite a bit of rice to make reasonably sturdy patties. In this case, I have about 1.5 cups of sprouted brown rice; add the oil needed to cook it, and the calories add up. You could make the patties smaller in diameter (mine are about 4.5inches / 11.5cm) and use less rice, but I do like my burgers to be two-fisted. The filling here is quite low in calories though, so that helps to balance things out. As I’ve noted, the total calories for the rice burger in this bento is around 350 calories, which is not bad I think. Watch out when you use higher-calorie fillings like beef burgers though if you’re watching your waistline!