Heat 1 tbsp oil in a large nonstick pan. Add the shallot or onion, garlic and chilli, and cook for 3 minutes or until softened. Stir in the rice, stock and coconut cream. Season lightly.
Bring the rice mixture to the boil. Stir once, then lower the heat to a gentle simmer. Cover and cook for 10 minutes without lifting the lid, or according to the pack instructions. The liquid should have been absorbed and small steam holes should have appeared. If necessary, cover and cook the rice mixture for a further 2 minutes. Add the cucumber slices and cook, covered, for a further minute, then remove the pan from the heat and leave for 5 minutes.
While the rice is standing, heat the remaining oil in a wok or large pan and stir-fry the prawns for 3 minutes or until they turn pink. Stir in the cumin and cook for a few seconds, then add the lime juice.
Reserve a few whole coriander sprigs and roughly chop the remainder (including the stalks). Add to the prawns and stir. Divide the rice among four plates and top with the prawns. Garnish with the coriander sprigs and serve with the lime wedges.