Mince any reserved leftover fat. Transfer to a small saucepan. Cook over medium-low heat until fat is heated through, about 3 minutes( fat will not melt completely ).
Add all ingredients and cook until just heated through; keep warm.
Build a medium fire in a charcoal grill, or heat a gas grill to medium-high. Grill skewers, brushing with basting sauce and turning every 2 minutes, for 10 minutes. Stop basting and cook turning every 2 minutes, until browned around edges and cooked through, about 6 minutes more. Serve with scallion dipping sauce on the side.
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