Step 1Combine the tamarind paste, palm sugar, fish sauce, and ¼ cup water in a small saucepan. Hold ½ cup coconut in your hands and rub between your palm and fingers to crush it into small crumbles into the pan. Bring to a gentle simmer over medium-high heat, stirring often. Continue cooking, stirring occasionally, until the sugar melts and the sauce reduces slightly, about 5 minutes. Cool completely.
Step 2You want to cut the filling ingredients into the same size as the whole peanuts. Cut the lime into ½-inch wedges, then cut each wedge into ¼-inch slices. Cut the ginger into ¼-inch slices at an angle. Quarter the shallot lengthwise, then cut into ½-inch chunks.
Step 3Put a nasturtium leaf stem side down on a work surface. Mound a tablespoon of coconut in the center, then top with a lime slice, ginger slice, shallot chunk, peanut, chile half, and shrimp. Dollop a spoonful of sauce on top. Repeat with the remaining ingredients. To eat, wrap the sides of the leaf all around the filling to form a little pouch and stuff into your mouth in one bite.