1. In a large saucepan, boil 3 cups of water and add in the salt.
2. Stir in the rice and let it cook for 17 minutes.
3. In another saucepan, heat vegetable oil and add in the ground ginger and onion. Sweat for a few minutes.
4. Add in the red Thai curry paste and cook for 1 minute.
5. Stir in the canned tomatoes and mix well.
6. Add in the lemon grass and coconut milk. Stir well and bring to a boil and simmer for 5 minutes.
7. Stir in the prawns and stir well. Simmer for 5 minutes. Take out the lemon grass and discard.
8. In a serving plate, place the rice and top with prawn curry. Garnish with coriander and serve.