Spread out bacon on a large, lightly greased piece of foil and grill for 15 minutes or until nice and crispy. Remove and crumble. Add shrimp to remaining bacon fat and grill for about 3-4 minutes on each side or until grey color has turned white.
In a skillet over medium heat, sauté the onions in butter until translucent. Add garlic and sauté for a minute then stir in crushed pineapples and tomatoes and keep heated on low until ready to serve.
In a microwavable large bowl, prepare grits using the microwave as directed on the package. Stir in cheese and salt.
Spoon grits onto a plate and layer with tomato pineapple sauce, crumbled bacon, and shrimp. Top with barbecue sauce and serve.