This technique has never been seen in its normal state but what is known is that its a mid-range ninjutsu.
Fire Monk Version
Gabimaru can use a Ninpō: Fire Monk version known as Ninpō: Wind Sewing — Fire Monk Version (忍法 風縫い 火法師拵え Ninpō: Kaze Nui — Hi Bōshi Bājon?). After combining Fire Monk with Wind Sewing, Gabimaru is able to expel a fireball from his mouth. This is called Ninpo: Zephyr Weave, Ascetic Blaze Mode in the Viz Manga.