Rinse and soak rice in a bowl of water for 50 minutes. Drain well and transfer rice to a rice cooker; add 2 cups water.
Cook rice according to manufacturer's instructions, about 20 minutes. Transfer cooked rice to a large bowl and cool for 2 minutes. Stir in sugar and butter.
Rinse and soak dates in a bowl of warm water for 30 minutes. Drain and slice dates in half and remove pits.
Mix red bean paste and walnuts together in a bowl.
Lightly oil a shallow bowl with vegetable oil. Place pineapple ring in the bottom and fill with pumpkin seeds and peanuts. Arrange dates and mandarin oranges around the pineapple ring, creating a sunshine pattern. Spoon 1/2 of the rice into the bowl and flatten. Spread red bean paste mixture evenly on top. Fill the bowl with the remaining rice and flatten.
Place bowl in a steamer, cover, and steam over medium-high heat for 25 minutes. Remove from heat and cool for 5 minutes. Run a knife around the edge of the rice. Place a plate over the top, flip over, and remove bowl.