Place brown rice noodles in a bowl of very hot water and soak for 20 minutes until flexible but firm, then drain.
In a small bowl, whisk together the fish sauce, tamarind paste, coconut sugar, and lime juice until the sugar is dissolved.
Heat avocado oil in a large wok or skillet over medium-high heat and sauté the minced garlic and red pepper flakes for 30 seconds.
Add the shrimp to the pan and cook for 2 minutes per side until pink and opaque, then push them to one side of the pan.
Crack the egg into the empty side of the pan, scramble it quickly until set, and then toss it with the shrimp.
Add the soaked noodles and the prepared sauce to the pan, tossing constantly for 2 minutes until the noodles are tender and coated.
Stir in the bean sprouts and sliced green onions, cooking for just 30 seconds more to maintain their fresh crunch.
Serve immediately topped with the crushed peanuts for a final layer of texture.