To cook the pork: In a pot over high heat, add the pork belly and ginger. Bring to a simmer and skim off any impurities. Lower the heat and simmer for about 30 minutes, or until the pork is cooked through. Let cool, then thinly slice.
To cook the shrimp: In a separate pot, boil the shrimp for about 2 minutes, or until pink. Drain and reserve 1½ cups of the shrimp cooking water. Slice the shrimp in half lengthwise and set aside.
To cook the rice vermicelli: Soak the rice vermicelli in water for 20 minutes. Boil for 3 minutes, or according to the package instructions. Rinse under cold water and drain well.
To make the peanut dipping sauce: In a small pot over low heat, add the avocado oil and garlic. Cook for 1 minute, or until fragrant. Add the peanut butter and hoisin sauce. Stir for 1 minute, then pour in the reserved shrimp cooking water. Stir constantly and bring to a boil. Set aside.
To make the nuoc cham: In a bowl, combine the hot water, sugar, fish sauce, lime juice, garlic, and sliced chili peppers. Stir until the sugar dissolves. Adjust to taste if needed.
To assemble the spring rolls: Prepare a wide plate of water. Dip one rice paper wrapper into the water for about 1 second, then lay it flat on a clean work surface. Layer the lettuce, mint, cilantro, cucumber, bean sprouts, rice vermicelli, and pork slices near the bottom edge. Fold the sides inward and roll halfway up. Place 3 halved shrimp, pink side down, and a trimmed chive on top. Continue rolling tightly. Repeat with the remaining ingredients.
To serve: Arrange the Vietnamese Fresh Spring Rolls on a serving plate with the peanut dipping sauce and nuoc cham.