Soak the brown rice noodles in a bowl of hot water for 20-30 minutes until pliable but still slightly firm, then drain.
In a small bowl, whisk together the tamarind paste, fish sauce, and coconut aminos to create the savory pad thai sauce.
Heat the avocado oil in a large wok or skillet over medium-high heat.
Add the shrimp and cook for 2 minutes per side until pink and opaque, then remove from the pan and set aside.
In the same pan, sauté the minced garlic and sliced green onions for 30 seconds until fragrant.
Add the drained noodles and the prepared sauce to the pan, tossing constantly for 2 minutes to coat and soften the noodles.
Fold the cooked shrimp and mung bean sprouts back into the pan, cooking for 1 more minute until the sprouts just begin to wilt.
Serve immediately topped with crushed peanuts, red pepper flakes, and a fresh squeeze of lime juice.