Onigiri can be found in many different types of eateries throughout Japan and are a staple of many sushi shops and izakayas. The most common place to find onigiri are in combinis (convenience stores). These onigiri range from 100 to 150 yen and are typically filled with salmon, roe, pickled seaweed and most commonly tuna salad. The combini employees will usually ask you if you would like to heat the onigiri in the microwave, which can be a godsend on cold nights. As stated earlier, onigiri usually come in triangular or circular shapes.