Method:

1. Combine all marinade ingredients in a shallow dish and place tuna in a single layer turning to coat completely.
2. Cover with plastic wrap and refrigerate for four hours.
3. Bring back to room temperature before cooking.Prepare noodles as per instructions on pack. Reserve.
4. Brush the char grill with oil and grill the tuna and the spring onions, cooking the tuna no more than medium rare.
5. Arrange the noodles, spring onions and tuna on four plates and sprinkle the sesame seeds over the fish.