In bistro we left hand tool (6)
I believe the answer is:
trowel
'hand tool' is the definition.
(I know that trowel is a type of hand tool)
'in bistro we left' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TROWEL' can be found hidden inside 'bistro we left'.
(Other definitions for trowel that I've seen before include "One spreads" , "Plastering tool" , "Gardening implement" , "Small gardening tool for lifting plants" , "small digger" .)