Bring 2 tablespoons of oil to medium heat in a large skillet. Add sweet potatoes, 1 teaspoon of salt, and vegetable broth and toss to coat. Cook for 5 minutes, stirring occasionally.
Remove the sweet potato noodles from the skillet – set them aside in a bowl.
Add 2 tablespoons of oil to the skillet and return to medium heat. Toss scallions and garlic into the pan and saute for minutes.
Add lemongrass paste, ginger, and thai chiles and continue to stir.
Add peanut butter, tamari, and coconut milk and stir to combine. Cook the mixture for 10 minutes, stirring occasionally – the sauce will thicken in consistency.
Return the sweet potato noodles to the sauce and toss them to coat thoroughly – tongs work best for this.
Serve the noodles and garnish with chopped peanuts, cilantro, etc.