For the tuna, cut the slices approximately 1/4 - inches and an inch wide

For marinade, mix all of the ingredients together. Put tuna in marinade for 10- 15 minutes.

Meanwhile, prepare the sauces. For the sweet soy sauce: Heat soy sauce until it begins to boil. Whisk in sugar until all dissolved. Cook for a few minutes, careful not to let overflow. Finish with a spoonfull of butter. Cool.

For the spicy mustard, mix all of the ingredients together.

Place a piece of aluminum foil on edge of the grill until where you will rest the ends of the skewers. This will prevent the bamboo skewers from burning.

Skewer fish pieces one per skewer and grill until desired temperature is achieved, about 1- 2 minutes per side.

Serve on a bed of chiffonade baby spinache, watermelon cubes and black sesame seeds; use a dressing of 1 part lemon juice and 2 parts olive oil.