Prep the noodles: Start by placing your rice vermicelli noodles in a large bowl and pouring hot water over them. Let them soak for about 5 minutes, just until they’re softened. Drain them well, then divide the noodles into small nests and set them on a heatproof plate or shallow steamer tray.
Prep the shrimp: Butterfly each shrimp by slicing lengthwise almost all the way through, but don’t cut them in half completely. Gently press them flat, then make a small slit at the base and tuck the tail through—this creates the “boat” shape.
Season the shrimp: Toss the prepared shrimp with lime zest, fish sauce, and sesame oil. Place one shrimp on top of each noodle nest.
Make the garlic-chili butter: In a small saucepan over medium heat, melt the butter until it starts to bubble. Stir in the garlic and chili flakes and cook for 1 to 2 minutes, just until fragrant. Add the soy sauce, honey, rice vinegar, and a pinch of black pepper. Let it cook for another 30 seconds, then take it off the heat.
Steam and serve. Place the noodle nests with shrimp on a heatproof plate or shallow tray. Set inside a steamer basket over simmering water (or use a large lidded pan with a rack or makeshift setup). Cover and steam for 3–4 minutes, until the shrimp turn pink and are fully cooked. Drizzle with the remaining sauce, garnish with cilantro, and serve hot.