In a large pot over medium heat, add the oil, garlic, ginger, and Thai red curry paste. Fry for 5 minutes, until fragrant. Add the chicken and cook for a couple minutes, just until the chicken turns opaque.
Add the chicken broth, water, fish sauce, and coconut milk. Bring to a boil. At this point, taste the broth for salt and adjust seasoning accordingly (add salt if needed, or if it’s too salty, add a bit of water). Pour the boiling soup over the dried vermicelli noodles in your serving bowls, add a squeeze of lime juice and your garnishes, and serve. The noodles will be ready to eat in a couple minutes.
(Alternatively, you can add the noodles to the boiling broth to cook them, and then divide among serving bowls).