Severely criticised for being wrongly salted (6)
I believe the answer is:
'severely criticised' is the definition.
(slate can mean to criticise severely)
'wrongly salted' is the wordplay.
'wrongly' is an anagram indicator (I've seen this in other clues).
'salted' with letters rearranged gives 'SLATED'.
'for being' acts as a link.
(Other definitions for slated that I've seen before include "House roof may be - criticised" , "Berated with roofing material?" , "Gave a terrible review" , "Berated with roofing materials?" , "Torn to pieces" .)