Note: This article has been substantially improved and updated here , but I'm leaving this original as-is for the simpler approach using canned skins.
[Another update: Lower-calorie inarizushi  filled with a mixture of rice and hijiki seaweed
Being on the road  at the moment has given me some idle time on trains, in my hotel room, etc. to finally sort through some of my food pictures that I haven't posted about here. It struck me that a lot of the pictures were of round food, or food in rounds. Anyway, this is Round Food no. 1.
I think that the most popular post on this site is the one about onigiri , or rice balls. Onigiri are fun and tasty, and cute too, but the other kind of 'little handful of rice' food that I love is inarizushi. Inarizushi is also called o-inari-san in Japan, a sort of term of respect and endearment combined. Inari also the name of a Shinto diety  (it's a bit fuzzy as to whether a god or goddess). O-Inari-san the diety has many little shrines scattered on roadsides around Japan, as well as many temples, but the most endearing homage to him/her is probably o-inari-san the rice snack.
Basically, inarizushi is a fried tofu skin (aburaage) that's been cooked in a sweet-soy sauce based sauce, drained then stuffed with sushi rice. It's the type of homey sushi that you never see in sushi restaurants, though you do see them more often nowadays at take-out obento or sushi places. It can be time consuming to make if you start from scratch - that is, preparing the skins to make the bean bags. However, here I give the cheat version: using prepared bean bags. These are a bit more expensive than the unprepared fried tofu skins, but you do save a whole lot of time and effort.
The prepared bean bags are available either canned or in a vacuum-packed variety. I use the canned kind because they are just as good as the other kind, but a bit cheaper. Look for them in Japanese or Korean food stores - either ask for Inarizushi no moto or look for English translations on the cans that say something like Prepared Fried Bean Curd Skin or something like that. The brand I use is Santa, which has a very rotund old Santa Claus as the trademark. The skin is quite sweet, while the filling has that salty/sweet/sour taste of sushi rice, and it all goes together marvelously. if you supply moistened towels to wipe fingers they make great party food, since the bags prevent the rice from drying out. It's actually even better after they have 'rested' for an hour or so, since the flavor of the skins penetrates into the rice.
The picture makes the little bags look rather oily, but they aren't at all: the shine comes from the soy sauce, mirin (sweet rice wine) and sugar in the cooking liquid. For people who are inclined to make everything from scratch I've also included a recipe to make the bags from plain aburaage, but using the recipe I posted here before for Japanese essence in a bottle .
To make 16 o-inari-san:
Prepare the sushi rice, but add an extra bit of salt and a teaspoon more of sugar to the sushi vinegar mix. Let cool to room temperature, following the instructions .
Take the bean bags out of the can carefully, and drain off the liquid. Drain each one by squeezing very gently in your hand. You'll notice that each 'bag' has an open end and a closed end; carefully pry open the open end and hold the bag in your hand. Make ready a cup or water or wa ter and vinegar, and dip a tablespoon into it before taking a rounded spoonful of the rice. Stuff the rice into the bag. Some people find it easier to take a small handful of rice in a moistened hand, squeeze gently then stuff into the bag. You don't want to overstuff the bags, or they will tear.
Close up the bag, and place open-end down on a plate. You can garnish this with gari (pickled sushi ginger) if you like.
Variation You can mix in some toasted white sesame seeds (not gomashio, which would be too salty) into the rice, or flaked salmon, etc. but they are really best just plain.