The previous night, place your pork roast in a large non-reactive container with fitting lid. Mix water and salt together and pour over the roast. Cover and refrigerate overnight.
In the morning, take roast out of fridge, rinse and place in Dutch Oven or large oven safe saucepan with fitting lid.
Combine pineapple, coconut milk, coconut aminos, garlic, ginger, chili pepper, rice vinegar, sesame oil, salt, pepper and Chinese 5 spice in your high speed blender and process until smooth.
Pour that pineapple mixture over the roast and marinate for 2 to 3 hours.
Preheat the oven to 325F. Slide the roast in the oven, covered, where it will remain for a total of 5 hours. Every half hour or so, you'll want to take the roast out of the oven and baste it with the cooking liquid.
After 2½ hours of cooking, crack open the lid just a little bit to allow some of that cooking liquid to evaporate.
Completely remove the lid for the last half hour of cooking, after basting one last time. This will ensure that the top gets nice and golden brown as well as make that sauce really nice and thick.
Remove roast from the oven; carefully lift it with 2 large forks and place it on a serving plate. Tent it loosely with aluminum foil to keep it warm while you work on the sauce.
Add a cup of coconut milk and the juice of half a lime to the cooking liquid that's left at the bottom of the Dutch oven and mix well.
You could serve it as is, but for a sauce that's got a really smooth and silky consistency, pour it through a fine mesh sieve and help it through by pushing it down with a ladle in a circular motion. Don't forget to scrape the underside of your sieve with a rubber spatula!
Slice the roast and serve with the sauce on the side.