The user unleashes a volley of shuriken with one hand, and at the same time, exhales fire-infused chakra onto them in order to increase the weapons' destructive potential by making them capable of inflicting severe burns upon direct contact with either the intended victim, or any other object caught within their trajectories.
Due to the chakra-based nature of the flames that surround them, the shuriken will continue to burn after impact, regardless of the flammability of the object that they ultimately collide with.