For the sweet potato mash: Preheat the oven to 375 degrees F. Roast the sweet potatoes until completely soft, about 1 hour 30 minutes. While still warm, peel the potatoes and add them to a food processor. With the machine running, add the vinegar, butter and salt and pepper to taste. You may need a little water to get the mixture to puree, but don't add too much. Reserve.
For the collard greens: Saute the onions in a large, wide-bottomed pan. Sprinkle with salt, and then add the greens, a bit more salt and about 1/2 cup water. Slowly cook the greens with the smoked pig's foot over low heat for at least 1 hour 30 minutes. The water will evaporate and draw the moisture from the greens. Stir occasionally and let them do their thing. Finish the dish by adjusting seasoning with salt, pepper and vinegar.
Turn the oven temperature to 450 to 500 degrees F.
Remove the chicken from the brine and let it rest and come to room temperature. Dry, and sprinkle with salt and pepper.
Get your saute pan medium hot; add a good amount of canola oil. Crispy brown skin is the goal here, so mind your heat. Don't burn it, but make sure the pan is hot enough to keep the chicken from sticking. Add your chicken skin-side down and shake the pan to make sure the skin is not sticking. Add a weight of your choice (we use antique bricks we found in our building, hence the name), and then transfer the pan to the oven. Let it roll for about 10 minutes. Carefully flip the chicken over and let it go for another 6 minutes. All ovens are different, so after the chicken rests for 4 to 5 minutes, check the temperature in the leg to make sure it is thoroughly cooked.