How about a reaction or bonus action cantrip?
Casting Time: bonus action or reaction
Range: 30 feet
You snuff out a fire no bigger than 5 feet square. If the fire is non-magical, then the fire instantly goes out. If the fire is magical and from a spell higher then level zero, then this spell has no effect. If a character is on fire and a saving throw can end the effect, then the character gets another saving throw regardless of the spell level causing the fire effect.