。
She wants to expand the no-smoking area.
Literal
She [topic-は] no-smoking area [object-を] want-to-widen [quotative-と] is-thinking.
禁煙 ('no smoking, smoking ban') is built compactly: 禁 ('prohibit') + 煙 ('smoke'). The same productive 禁~ prefix forms 禁酒 ('alcohol ban'), 禁止 ('prohibition'), 禁忌 ('taboo'). ~たいと思う ('I'd like to / I want to') is a softer way to express desire than bare ~たい — wrapping the desire in と思う adds a hedge of 'thinking' rather than asserting outright. Public-place smoking restrictions have expanded significantly in Japan in the 2010s and 2020s; this sentence has the feel of an advocacy comment.