Place a skillet on the grill. Cook the onions and green peppers with some oil in the skillet for 3 to 4 minutes.
Add the beans, tomato sauce, ketchup, brown sugar, mustard, vinegar, cayenne, chili powder, smoked paprika and garlic and stir. Cook with the grill covered, stirring occasionally, for about 15 minutes. Garnish with green onions, if using.
Add your favorite meat to these beans for a heartier meal!