Grate the inside of the lemongrass (white and light green parts) with a microplane. Place shrimp in a bowl with the lemongrass, toasted sesame oil, ginger, lime, soy sauce, and a pinch of salt and pepper. Toss to combine ingredients and marinate for a maximum of 15 minutes. Meanwhile, make the dipping sauce. Using a blender, pulse all ingredients until creamy. Season to taste with salt and refrigerate for at least an hour. Optional: garnish with chopped peanuts and 1 sprig of Thai basil.
Preheat oven to 400ºF. Place shrimp on a baking sheet and roast for 6-7 minutes. Cut through one to make sure it’s opaque in the center. Let cool and cut each shrimp into thirds.
Set out an assembly line of ingredients starting with the rice paper rappers, a rectangular platter of warm water and a damp, outspread dishcloth for the wrappers. Next, the pea shoots, herbs, cucumbers, and carrots. Have a serving platter ready at the end. Submerge a wrapper in the water for about 5 seconds until it feels pliable. Carefully transfer to the damp towel. Equally layer all ingredients across the lower third of the spring roll skin.
Fold sides over filling (like a burrito) and continue to roll away from you until the edges are sealed. Transfer wrapped summer roll to the serving platter and repeat until all rolls are completed. Serve immediately with peanut dipping sauce.