Heat the oil in a wok or saucepan and stir-fry the curry paste over a medium heat for 3–4 minutes or until fragrant.
Add the roasted duck and stir for 3–4 minutes. Add the coconut milk, stock or water, fish sauce and sugar or honey and simmer over a medium heat for 3–4 minutes or until the sugar has dissolved. Add the lychees, tomatoes and kaffir lime leaves in the last few seconds, taking care not to let the tomatoes lose their shape. Taste and adjust the seasoning.
Spoon into 4 serving bowls and serve with cooked rice and steamed vegetables, or spoon over cooked noodles.