Place the rice in a pot (that has a fitted lid) and cover it with the water; add the salt. Bring to a boil, then reduce the heat to very low. Cover and cook for about 30 minutes, or until the water has been absorbed and the rice is cooked through. Spread the rice out on a rimmed baking sheet to cool to room temperature.
Pour the orange juice into a small saucepan over medium-low heat. Simmer until it has reduced to ¼ cup. Swirl in the orange segments and the honey; set aside.
Pat the prawns dry with a clean dish towel or paper towels. Sprinkle with salt and pepper. Heat a large skillet with enough olive oil to evenly coat the bottom of the skillet (1 to 2 tablespoons). When the oil is shimmering and quite hot, add the prawns in a single layer—you may have to work in batches. Do not move them for 1½ minutes, or until a seared golden crust is formed, and then flip them and cook about 1 minute longer, until just cooked through. Transfer the prawns to a plate.
Add about 2 tablespoons of oil to the skillet and add the rice. Cook for 1 minute, stirring frequently, then add the curry powder and coconut milk. Cook for 1 additional minute, then toss in the spinach.
Spoon the rice onto individual serving dishes and top with the prawns. Spoon the orange sauce over the prawns and serve immediately.