Son with us greeting Japanese dish (5)
I believe the answer is:
sushi
'japanese dish' is the definition.
(type of Japanese food)
'son with us greeting' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'with' is a charade indicator (letters next to each other).
'greeting' becomes 'hi' (hi is a kind of greeting).
's'+'us'+'hi'='SUSHI'
(Other definitions for sushi that I've seen before include "Japanese food" , "Japanese vinegared rice dish" , "Japanese rice-based dish" , "Asian dish" , "exotic dish" .)