In a food processor, pulse the ginger with the garlic, jalapeños, lemon juice and paprika until finely chopped. Add the water and process to a paste.
In a large saucepan, heat 2 tablespoons of the oil until shimmering. Add the onions and cook over moderate heat until softened, about 8 minutes. Add the ginger paste and cook until it begins to brown, about 3 minutes. Add half of the tomatoes along with the coconut milk, peanuts, 1/4 cup of the shredded coconut and 2 tablespoons of the cilantro and cook until slightly thickened, about 5 minutes.
Scrape the sauce into a food processor or blender and puree. Return the sauce to the saucepan. Add the stock and the remaining tomatoes and 2 tablespoons of cilantro and bring to a boil. Season with salt and pepper and simmer over moderate heat until reduced to 5 cups, about 20 minutes. Keep warm.
Meanwhile, in a large nonstick skillet, heat the remaining 2 tablespoons of oil until shimmering. Season the chicken with salt and pepper and sauté over moderately high heat until golden and cooked through, about 10 minutes.
Add the chicken; season with salt and pepper. Spoon into bowls and garnish with coconut and cilantro. Serve with steamed rice and lemon wedges.