Wash the rice. Cover with 10 c water & soak for at least 6 hours or overnight. Drain.
Simmer adzuki beans in 3 c water over medium heat for 40 minutes. Cook until they are tender but not mushy.
Put coconut milk in a large pot. Add salt & sugar & bring to a boil over medium heat. Add the rice & cook, stirring constantly, until all the milk has been absorbed.
Cut bananas in half lengthwise then cut in half crosswise. Put 2 tb rice in the middle of each peice of foil. Flatten & place a banana quarter on top. Arrange adzuki beans around the edges. Cover with another 2 tb rice. Flatten to cover the banana. Bring two long sides of the foil up to meet above the rice. Fold twice & press down on the rice. Steam over medium heat for 20 to 25 minutes. Serve warm or at room temperature still in wrapper.