Heat the vegetable oil. Add the ground chicken and begin to saute, mashing the chicken with the side of a wooden spoon, continuously moving it and mashing it so that it crumbles. After 3 minutes, add the garlic and ginger and cook for about a minute or until the moisture has evaporated and the chicken begins to dry out. Add the water and chicken broth and bring the liquid to a boil. Add 1 teaspoon of salt and the vermicelli. Cover the pan and cook until the pasta is tender, about 5 minutes. While this is cooking, juice the limes, slice the scallions into 1/4-inch rounds, and roughly chop the coriander. When the vermicelli is tender, remove the saucepan from the heat, stir in the lime juice and coconut milk, and season to taste with salt and dried pepper flakes.