Yeah you can say "That girl is smoking!" or "That girl is smoking hot!" It's a slang term that describes an attractive girl. She is so "hot" that she is "smoking"

You are right, smoking can have the meaning sexy. You can say "that girl is smoking!" which can literally mean that she is smoking a cigarette or that she is hot or sexy.

It depends mainly in the context, the comment is stated in. "A girl who smokes" could only be a girl who smokes cigarettes and things of that nature. However.... "A smoking girl" could be a girl who smokes, if the tone is literal. If the tone is somewhat playful and uses slang occasionally, it just means a girl who is very attractive and sexy. Smoking is inferred from when people use the slang "hot" to describe a person's appearance rather than temperature.

Smoking girl is havitual of smoking but girl who smoke is not havitual of smoking she smoke sometimes.

楼上的说的都没错，不明白为什么都是thumb down，请大家评判的时候客观一点