Finely dice the onion and Chop the leek into 2 cm pieces.
In a medium sized bowl add all the Tsukune Ingredients and mix together well.
Divide the Tsukune mixture into 12 and roll out to make a ball shapes.
Skewer the mince balls alternatively with the leeks, press the ball shape to stretch the mince around the skewer. Make 4 skewers, lightly varnish with oil.
For the Tare sauce simply combine all the ingredients and stir well.
At the barbecue:
Prepare the barbecue for direct heat approx. 220°C If using a charcoal barbecue, you need ¾ chimney starter of lit briquettes.
Preheat your grill for 10 minutes with the lid closed.
Add the Tsukune to the Grill and cook over direct heat for 3 minutes.
With a fish slice turn the Tsukune and cook for a further 3 minutes, or until the core temperature reaches 75°C.