Prepare the Peanut Sauce: In a small bowl, whisk together the peanut butter, soy sauce, rice vinegar, maple syrup, and garlic.
Gradually add the warm water, whisking until the sauce is smooth and creamy.
If desired, add a pinch of crushed red pepper flakes for a little heat. Set the sauce aside.
Assemble the Spring Rolls: Fill a shallow dish or pie plate with warm water.
Dip a rice paper wrapper into the water, one at a time, until it becomes pliable, about 20-30 seconds.
Transfer the wrapper to a clean, damp work surface.
In the center of the wrapper, place a small mound of shredded cabbage, carrots, cucumber, and bell pepper.
Top with a few mint and cilantro leaves.
Fold the bottom of the wrapper over the filling, then fold in the sides and roll the wrapper tightly to enclose the filling.
Repeat with the remaining wrappers and fillings.
Serve the fresh spring rolls with the peanut sauce for dipping.