Lightly grease the grates of your grill to help prevent the salmon from sticking when you turn in.
The barbecue sauce can be made several days in advance. Keep it in the refrigerator until ready to use.
4salmon filletscut into large cubes (about 2 pounds)
Instructions
Heat the oil in a small pot over medium heat. Add the onion and garlic and cook, stirring frequently, until softened and golden brown, about 5 minutes. Stir in the ketchup, vinegar, syrup, mustard, and hot sauce (if using). Bring to a rapid simmer and cook 5-10 minutes, or until the sauce is thickened. Remove from heat.
Thread the salmon cubes onto skewers. Brush liberally with barbecue sauce.
Grill over medium-high heat for 6-8 minutes on each side, brushing with additional sauce as the skewers cook.