Jonathan Owens had full control of Simone Biles' flames on Halloween ... grabbing a handful of his future wife in some steamy fireman-costumed pics!!
The Olympic gold medalist shared the hot photos on Sunday ... showing the Houston Texans safety getting a little handsy for the October holiday.
Biles was rockin' a 2-piece 'fit with flames all over it ... while Owens -- wearing fireman overalls and an FD cap -- made sure the blaze didn't get too out of control.
Biles asked her 6 million IG followers to give the sexy post a caption .