Wash the spring onions. Finely chop the white, cut the green into fine rings (for decoration).
Heat the oil. Fry the white spring onions, ginger and chilli in it. Deglaze with coconut milk and vegetable stock and simmer for about 4 minutes. Then add the shrimp and diced tomatoes to the soup and let them get hot.
Season with soy sauce and lime juice and sprinkle with the green spring onions before serving.