Place roast in slow cooker, then sprinkle with paprika, brown sugar, salt, pepper.
Top with chopped onion, tomatoes, and vinegar.
Cover and cook on high for 6 hours or low for 9 hours, until the roast is falling apart tender. In a Dutch Oven in your oven, cook at 275 F for about 5-6 hours. Check periodically to make sure you don’t need to add additional liquid (this will depend on the tightness of your seal.).
Remove roast to a separate platter. If your tomato mixture is not thick enough, pour the remaining sauce into a saucepan to heat and thicken or if in Dutch oven, you can heat in the pan on the stove until thickened.
Shred meat, discarding fat and bone. Check carefully for small pieces of bone.
Return shredded meat to the sauce and stir together smashing up any large pieces of tomato in the sauce.
Serve warm on toasted buns or see other serving suggestions below.
Notes
Using fresh tomatoes will make it more likely that you'll need to reduce the sauce afterwards.
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.