Some characters in salon arguing over breakfast? (7)
I believe the answer is:
granola
'breakfast?' is the definition.
(I've seen this before)
'some characters in salon arguing over' is the wordplay.
'some characters in' indicates the answer is hidden within the clue.
'over' shows that the letters should be reversed in order.
'alonarg' is hidden within 'salon arguing'.
'alonarg' backwards is 'GRANOLA'.
(Other definitions for granola that I've seen before include "US breakfast cereal" , "breakfast dish" , "type of cereal" .)