What is this smoking item in Beyond the Boundary?
This is what is commonly known as a "mosquito coil." These are mosquito-repelling incense, in spiral-shaped (this particular shape was popularized in Japan) and made up of a dried paste of pyrethrum powder.
I japan it's called "katori senkou" and it's usually green-ish swirly incense-like item, that you set on light and burn slowly. The smoke/smell that comes from it keeps the mosquito away.

As you may or may not know, just about all chemical repellents and insecticides contain pyrethroid, which is a chemical imitation of Pyrethrin, found in pyrethrum.