1. Combine the rice and 2 cups of water in a medium saucepan. Bring to a boil, reduce the heat, cover and simmer for 15 minutes, or until all of the liquid is absorbed and the rice is tender. Remove from the heat and let sit covered for 10 minutes. You can also prepare the rice in a rice cooker according to manufacturer instructions.
2. In a small bowl, stir together the grapefruit juice, rice wine vinegar, sugar and salt until the sugar and salt are dissolved.
3. Transfer the rice to a large bowl. Pour juice and vinegar mix over the rice. Use a spatula to spread and stir the rice, coating it with the liquid as it cools. Let cool to room temperature.
4. Divide the rice into 4 bowls. Top each with 2 ounces of crab, 2 tablespoons of carrot and 1 tablespoon of black sesame seeds.
5. Halve and pit the avocado and cut the flesh into small cubes. Transfer the cubes to a bowl and add the grapefruit segments. Toss to mix.
6. Add an equal amount of the grapefruit and avocado to each bowl. Top each with the desired amount of wasabi paste and serve.
Recipe courtesy of Wonderful Citrus.