Cook the pork in boiling salted water until it?s done but still firm enough for slicing, about 30 minutes.
While the pork is cooking, bring another small pot of water to a boil. Add the shrimp and cook until they turn pink, about 3 minutes. Rinse under running water and set aside to drain. When cool enough to handle, peel, de-vein, and cut in half lengthwise. Refresh in cold water and set aside.
Remove pork from the heat and drain. When it is cool enough to handle, slice into thin slices, about 1 by 2 1/2 inches. Place on a small plate and set aside.
Set up a salad roll "station." Line a cutting board with a damp kitchen towel. Fill a large bowl with hot water and place it nearby. (Keep some boiling water handy to add to the bowl.) Arrange the ingredients in the order they will be used: the shrimp, pork, rice vermicelli, bean sprouts, mint and lettuce.
Working with 2 rice paper rounds at a time, dip 1, edge first into the hot water and turn it to wet completely, about 10 seconds. Lay the round down on the towel. Repeat with the second rice paper and place it alongside the first. This allows you to work with 1 while the second is being set.
Line the bottom third of the rice paper round with 3 shrimp halves, cut side up, and top with 2 slices of pork. Add 1 tablespoon rice vermicelli, 1 tablespoon bean sprouts, and 4 to 5 mint leaves. (Arrange the ingredients so the rolls will end up being about 5 inches long and 1-inch wide.) Halve a lettuce leaf lengthwise along the center rib. Roll up in 1 piece and place on the filling. (Trim if it?s too long.) While pressing down on the ingredients, lift the bottom edge over the filling, then fold in 2 sides. Roll into a cylinder about 1 1/2 inches wide and 4 to 5 inches long. If the paper feels thick, stop three-quarters of the way and trim the end piece. (Too much rice paper can make the rolls chewy.) Repeat with the remaining rice papers and filling.
To serve, cut rolls into 2 or 4 pieces and place them upright on a plate. Serve with the sauce on the side.
Place the soybeans, water, coconut milk, vinegar, onion and sugar in a blender or food processor and process just until smooth. Transfer the mixture to a saucepan and bring to a boil over moderate heat. (If you don?t have a food processor, cook the soybean mixture first, then beat with a whisk.) Reduce the heat and simmer until the sauce thickens enough to coat a spoon, about 5 minutes. Add a little water if it?s too thick. Set aside to cool.
To serve, transfer to individual sauce bowls and garnish each with chile paste and chopped peanuts. This sauce will keep up to 2 weeks if refrigerated in a tight-lidded jar.
Cook?s Note: To cook bun, boil until the noodles are white and softened but still resilient, about 4 to 5 minutes, drain, rinse immediately in cold water and drain completely before serving.
Place the peanuts on a cookie tray and bake in a preheated 325 degree F oven until golden, about 20 minutes. Halfway into the baking, gently shake the tray so the peanuts roast evenly. (You can also roast the peanuts in a dry pan over low heat). Remove and set aside. Use the peanuts whole or coarsely chop them with a mortar and pestle, a food processor or a knife.
Yield: 1 cup