Rice balls can be made with different types of rice, including glutinous rice and rice, depending on the region and style of preparation. Sticky rice. Glutinous rice is often used to make traditional sticky rice balls and other traditional delicacies due to its sticky consistency and unique texture. In some regions, glutinous rice is also mixed with rice to balance the texture and viscosity. Rice. In some cases, especially when making sushi rice balls, specialized rice is used, such as Japanese sushi rice, which has the right firmness and viscosity for making sushi rice balls. In general, the main ingredient of onigiri can be glutinous rice, rice, or a mixture of both, depending on the choice of the maker and the traditions of the region.