Put 1 cup of the water and the miso in a small bowl and stir together. In a large pot, combine the remaining 5 cups water, the peas, green onions, jalapeno pepper, and garlic. Cover and bring to a boil over medium-hight heat, then immediately reduce the heat and simmer for 3 minutes. Stir in the miso mixture, dulse, lemon juice, and hot sesame oil. Bring barely to a simmer over medium-high heat. Serve immediately.