Using a food processor, puree pork, sugar, water and salt until completely smooth.
Make 4 equal patties of that puree on a nonstick foil or parchment paper.
Then, gently press another sheet of nonstick foil or parchment paper onto the top of those patties.
Freeze those patties for few hours until they become solid.
To make sandwiches, preheat a large skillet over medium heat.
In the meanwhile, slice the rolls to separate top and bottom.
Using a pan, brown the faces of top and bottom.
Now, using the same pan, cook those patties on each side for 3 to 4 minutes.
Let them cool for a while. Take a large bowl and pour 1 cup of barbecue sauce into it.
Dip pork patties into the sauce using tongs or hands.
Make sure patties are completely covered in sauce and then place them in a sandwich roll.
Then put 2 pickle slices and 2 tablespoons chopped onion on patties.