Heat a wok and add 2 tbsp groundnut oil. Fry the onions over a medium heat for 5-7 minutes until softened and slightly caramelised. Add the ginger garlic and chilli and fry off for a few minutes. Next add the spices and allow them to fry off before adding a pinch of salt. Add the coconut milk and simmer uncovered for about 5 minutes.
Season the sauce with the soy, sugar and lime juice. Add the chicken, prawns and tomato and cook for 3-5 minutes until the meat is cooked though. Taste and adjust the seasoning if needed. Mix through the fresh coriander just before serving.