One smearing last of teriyaki dish into both hands (8)
I believe the answer is:
libeller
'one smearing' is the definition.
(libel is smearing a person)
'last of teriyaki dish into both hands' is the wordplay.
'last of' indicates one should take the final letters.
'dish' becomes 'belle' (both can mean someone beautiful).
'into' means one lot of letters goes inside another.
'both hands' becomes 'LR' (abbreviation for left and right).
The last letter of 'teriyaki' is 'i'.
'i'+'belle'='ibelle'
'ibelle' placed within 'lr' is 'LIBELLER'.
(Another definition for libeller that I've seen is " Person who publishes false statements about another".)