(At what temperature) can salt evaporate?
All substances may have a melting and boiling point. I say "may" because in some instances there can be decomposition, for example, before reaching either temperature.

Sodium chloride has a melting and boiling point. Check Wikipedia:

https://en.wikipedia.org/wiki/Sodium_chloride

The sidebar lists the melting point at 801 °C (1,474 °F; 1,074 K) and the boiling point at 1,413 °C (2,575 °F; 1,686 K). The values are relatively high being consistent with the ionic nature of NaCl.