Whisk hot water and sugar in a bowl until fully dissolved, then stir in chile, lime juice, and fish sauce until well combined

Set the sauce aside to allow the flavors to meld and develop

In a separate bowl, whisk hoisin sauce and peanut butter until smooth, then add rice vinegar and chili garlic paste and mix until glossy and creamy

Adjust consistency with a small splash of warm water if needed and set aside

Combine water, sugar, rice vinegar, and salt in a saucepan over medium heat and stir until the sugar dissolves

Add shrimp and gently simmer while stirring until pink, curled, and just cooked through, then transfer to a bowl to cool slightly

Bring a pot of salted water to a boil and cook rice noodles until tender

Drain and rinse under cold water to stop cooking and keep the noodles springy

Toss cooled noodles with a portion of the citrus sauce until evenly coated

In another bowl, toss lettuce, carrot, and cucumber with additional citrus sauce until lightly dressed

Divide noodles among serving bowls and arrange vegetables alongside

Top with shrimp, avocado slices, fresh herbs, and roasted peanuts

Serve with peanut sauce on the side for drizzling