Rinse the rice in cold water, then drain. Add the rice along with the carrot juice, orange juice and 50ml water to a saucepan. Stir in the ground cumin and salt, then bring to a boil. Cover and simmer for 10 minutes, then turn off the heat and leave to stand for 30 minutes. Uncover and leave to cool.
Shape the rice into 16 balls, pressing firmly with your hands. If the rice sticks to your hands, lightly sprinkle them with water when rolling.
Make the pumpkin stems by sticking the green bean tips on top of the balls. Make the eyes and mouths by cutting the olives into shapes and pressing into the rice balls.