In a large saucepan, heat 2 tablespoons of canola oil. Add the mushrooms and cook until slightly colored. Remove from the pot.
Add another drizzle of oil, along with the onions, carrots and scallions to the pot and sauté until aromatic and nearly translucent, 5 minutes. Add the garlic, ginger, curry paste and a pinch of salt. Sauté until fragrant, 1-2 minutes. Stir in the chicken stock and coconut milk and bring to a simmer.
Add the mushrooms back to the pot, along with the chicken. Bring to a boil, reduce the heat to a simmer and cook for 10-15 minutes, until the chicken is cooked through. Season to taste.
Place the rice noodles in a heatproof bowl. Bring a kettle of water to a boil and pour boiling water to cover the noodles. Let sit for 10 minutes, or until pliable. Drain the noodles.
Divide the noodles between bowls and ladle in chicken soup. Garnish with mint, cilantro, scallions and lime wedges.