Brown the chicken: Heat a large skillet over medium heat and add the canola oil. Arrange the chicken in a single layer on a baking sheet and season with salt and white pepper. Turn the pieces over and season again. When the oil begins to smoke lightly, use a pair of metal tongs to carefully add the pieces, skin side down, to the skillet. Do not overcrowd the pan. Resist the temptation to move or turn the pieces, until they have browned on the first side, 5 to 8 minutes. Turn the chicken over and brown on the second side, 5 to 8 minutes. Transfer the chicken to a baking sheet and bake in the oven until cooked through, 15 to 18 minutes.
Cook the bacon: Add the bacon to the skillet you used to cook the chicken and cook until browned and crispy, 12 to 15 minutes. Transfer the bacon to a kitchen towel. Reserve the skillet.
While the chicken is cooking, make the sweet-and-sour sauce: In a medium saucepan, melt the butter over medium heat and add the onions and a pinch of salt. Cook, stirring from time to time with a wooden spoon, until they brown and become tender, 5 to 8 minutes. Add the white wine, 1/2 to 1 1/2 cups of water, the raisins, brown sugar, and red wine vinegar. Simmer, adding up to 1 more cup water if necessary, until the liquid reduces and the onions are cooked through, 12 to 15 minutes. Season with salt and white pepper.
Finish the dish: In the skillet you used to cook the bacon, pour off any excess grease and add the tomatoes. Simmer over medium heat until almost all the liquid is gone, 5 to 8 minutes. Pour the sweet-and-sour sauce into the skillet and then add the pieces of chicken and the juices. Bring to a simmer over medium heat and toss to coat the chicken with sauce. Taste for seasoning. Arrange the chicken in a single layer on a serving platter. Top with the bacon. Serve immediately.