Cook the rice noodles according to package directions, and rinse them with cold water to stop the cooking.
Bring the chicken broth with the shallot and the ginger to a simmer in a large soup pot or Dutch oven. Add the chicken, cover, bring to a simmer, then lower the heat and continue to simmer for 8 to 10 minutes until the chicken is cooked through. Remove the chicken to a platter with tongs, and let cool slightly, reserving the broth. Shred when it is cool enough to handle.
Meanwhile add the kale and coconut milk to the broth and return to a simmer over medium heat. Simmer for 5 minutes, until the kale is tender. Add the shredded chicken, cooked rice noodles, jalapeno, fish sauce, red pepper flakes, lime zest and juice and cilantro (if desired) and cook until it returns to a simmer, about 1 more minute.
Serve hot, in bowls.
You can take the seeds out for a milder soup, or leave them in for a bit more heat. For a very spicy soup use another jalapeno.