Criticise severely (4)
I think it could be either:
tear off a strip
(Other definitions for slam that I've seen before include "Ambitious contract" , "major contract" , "Severely criticise; shut (a door) forcefully" , "Shut loudly and forcibly" , "Winning of 12 or 13 tricks at bridge" .)
(Other definitions for tear off a strip that I've seen before include "Carpet" , "how to make it a bit narrower?" , "Reprimand" .)