MB3 148b: Chopping Salt and Grinding Meat on Shabbos (321:8-12)

Breaking apart blocks of salt with a pestle is prohibited, even for immediate use.

Cutting meat very finely with a knife is permissible (אין טחינה אלא בגידולי קרקע).

Grinding/grating cheese with a grater on Shabbos is prohibited.

Cutting vegetables very finely is prohibited.