Alaikumassalam wa rahmatullah,
Zunaira is a variant of Zinnaira and Zinneera, a Sahabiyya name, known as Zunairah al-Rumiya. She was a Roman (Byzantine) slave and became Muslim in Makkah in the early days of Islam. The pagans tortured her severely until she became blind and they said "our gods have made her blind", but she said "this is from my Lord [Allah], and He is able to bring my eyes back again" A day later she had her vision back and Abu Bakr purchased her from her torturers and gave her her freedom.
Both Zunaira and Zinneera are used to refer to her, and you can use either of them as a name. The meaning of the name is unclear since it doesn't originate from Arabic.