Trim and discard excess sinew and veins from the Sadia Chicken Livers, and place in a glass bowl. Add the vinegar and soy sauce and stir gently to combine. Set aside for 30 minutes.
Toast the Szechwan peppercorns and sea salt in a small frying pan over high heat. Using a spice grinder, grind together this mix until fine.
Preheat a grill plate and lightly oil. Thread the livers on to the skewers and grill a few minutes each side, until browned.
Serve sprinkled with the toasted salt and peppercorn mixture.