Preheat oven to 400?. Prepare brisket by trimming fat. place onions, garlic and water in a large dutch oven or stock pot. Rub salt, paprika, and pepper on brisket, then place on top of onions Pour tomatoes over meat. Cover pot with a tight fitting lid and place in oven. Cook for 15 minutes. Reduce heat to 325? and cook 2? to 3 hours or until a fork easily pierces the meat (Can be done up to 3 days ahead). Cool meat uncovered, then cover and refrigerate. Can be frozen for up to a month. Transfer meat to a plate. Spoon fat from top of braising liquid and reserve 1 1/3 cups. In the same pot, prepare bbq sauce. combine the reserved liquid with the rest of the sauce ingredients. Bring to a boil and then simmer stirring occasionally, for 20 or until flavors are blended. Can be made ahead. Preheat grill and have brisket at room temperature. Grill brisket 5-10 minutes or until heated through. Serve with sauce on it and as a side.