Is there any reference or source stating that the name "Zunairah" means "Flower of Paradise"?

First: "Zananir" (الزنانير) refers to small flies, or small pebbles. A woman described as "muzannarah" (مزنرة) is one who is tall and well-built.

Second: Zunairah (زنيرة) is the name of a female Companion whom Abu Bakr, may Allah be pleased with him, emancipated. She was tortured until she went blind, but Allah restored her sight. Abu Bakr purchased and freed her. It has not been mentioned in the available references that the meaning of the name "Zunairah" is "mountain flower."