In a large, heavy-bottomed pot or Dutch oven, add the bacon and canola oil, turn the heat to medium-high and cook the bacon until it starts to crisp, 4 to 5 minutes.
Add the red onions and green pepper, season with salt and pepper and saute over medium-high heat until the vegetables have softened, about 5 minutes. Add the beans, barbecue sauce, maple syrup, vinegar and mustard. Bring to a simmer, cover, reduce the heat to low and continue to cook the beans, about 45 minutes. Remove the lid and cook uncovered until the sauce has reduced and thickened and the flavors have developed, about 15 minutes. Just before serving, adjust the seasoning with salt and pepper.