Place pork side (belly) in large bowl with salt, cover with water, and let soak 8 hours, or overnight. Once soaked, remove pork from water and rinse well. Drain and cut into (2) 1¾-inch pieces.
Put lard into large skillet or frying pan over medium heat to melt. Once melted, add whole garlic cloves and pork pieces, lower heat, and cook gently 45 minutes, stirring occasionally.
Turn up heat and cook another 25 minutes, until meat has browned and fat is crisp and golden. Set aside.
Heat vegetable oil in large pan or deep fryer to 350°F, or until cube of bread browns in 30 seconds. Drop sweet potato slices carefully into hot oil and cook 5 minutes, or until crispy and golden. Drain well on paper towels.
To make Creole sauce, soak onion slices in iced water 5 minutes to crisp. Remove from water, drain, and place in bowl.
Add sliced chile, culantro or cilantro (coriander), and lemon juice to onion. Season with salt and mix together thoroughly.
To serve, slice bread rolls lengthwise down middle and fill with fried sweet potato slices, pork pieces, Creole sauce, onion, chile, and cilantro (coriander).