Place both types of peppercorns in a dry skillet and place over medium heat. Shake the pan over the flame until peppercorns are aromatic but not scorched. Using a spice grinder or a mortar and pestle, grind until coarse and gritty. Transfer to a shallow glass dish and add the salt, apricot preserves, garlic, fish sauce and lime juice. Reserve some lime zest for garnish, and add the remainder to the marinade. Mix to a sticky paste. Add the chicken and stir until well coated.
Preheat barbecue on HIGH, then reduce heat to MEDIUM.
Meanwhile, thread 4 pieces of chicken on each skewer. Grill 4 – 5 minutes per side.