Place the brown rice noodles in a large bowl and cover with very hot water; let soak for 8-10 minutes until softened but still firm, then drain.
In a small jar, whisk together the tamarind paste, fish sauce, coconut sugar, and juice from the half lime until the sugar is fully dissolved.
Heat the avocado oil in a large wok or non-stick skillet over medium-high heat, then add the shrimp and cook until pink and opaque, about 2-3 minutes.
Push the shrimp to one side of the pan, crack the egg into the empty space, and scramble it quickly until just set.
Add the drained noodles and the prepared sauce to the pan, tossing everything together for 2 minutes until the noodles are well-coated and tender.
Fold in the mung bean sprouts, sliced green onions, and red pepper flakes, then cook for one more minute until the sprouts are slightly wilted.
Plate the dish and garnish with the crushed peanuts for a satisfying crunch before serving immediately.