For sauce: In a small saucepan, heat 1 tablespoon oil over medium-low heat. Add garlic; cook, stirring, until lightly golden, about 1 minutes. Whisk in hoisin sauce and peanut butter. Add water to reach desired consistency. If you make the sauce ahead, reheat before serving.
For protein fillings: Simmer pork belly in salted water 45 minutes, then drain, cool and slice 1/4 inch thick. Poach shrimp in gently simmering water until opaque, 2 to 3 minutes; dunk in ice water, drain, and halve lengthwise. Fry tofu slices in canola oil until golden on both sides; drain on paper towels and cut into batons.
Arrange pork belly, shrimp, tofu, noodles, cucumber, peppers, lettuce, and herbs on platters so guests can make their own rolls.
To assemble, set a couple of medium bowls with very warm water around the table with rice papers next to them. For each roll, dunk a rice paper in the bowl, rotating if needed to moisten all over. (Depending how warm the water is, the wrapper needs as little as 5 or at most 15 seconds in the water; it should be pliable but not too sticky and will soften more as it is filled.) Shake off excess water and lay the paper on your plate with about 1/2 inch hanging off the edge closest to you. (That way, it's easy to pick up the paper and start rolling.)
Layer the fillings in the center. (Dang likes lettuce and noodles first.) Use the cucumber sticks to guide the length of your roll, and don't overfill or the roll will burst. Lift the edge of the paper away from you until it covers most of your filling. Fold the two sides in, then start to pull it toward you as you roll forward into a tight roll.