To make the dough, mix the rice flour with 1 1⁄4 cups hot tap water in a medium bowl and knead until a smooth dough comes together. Form into a disk and wrap in plastic until ready to use.
In a 1-qt. saucepan, bring the red beans and 2 cups of water to a simmer and cook until tender, 30 minutes. Drain the beans and spread onto a baking sheet; let dry for 1 hour. Transfer beans to a mini food processor with 1 tablespoon honey, 1 teaspoon sugar, a pinch of salt, and a pinch of nutmeg and grind into a paste. Transfer to a bowl and set aside. Wipe the food processor clean and add the chestnuts with another 1 tablespoon honey, 1 teaspoon sugar, a pinch of salt, and a pinch of nutmeg and grind into a paste. Transfer to another bowl and set aside. In a spice grinder, grind the sesame seeds into a paste, transfer to a bowl and mix with the remaining 1 tablespoon of honey, 1 teaspoon of sugar, a pinch of salt, and a pinch of nutmeg until incorporated.
Divide the dough into 40 tablespoon-size balls, about 1-inch in diameter, and using your thumb, push in the center of each ball to make a well. Scoop 1 teaspoon of one of the three fillings into the center and close it back up into a ball. Using your hands, mold the ball into a half-moon. Repeat this process alternating between the three fillings; you should end up with 10 sesame-filled cakes, 10 chestnut-filled cakes, and 20 red bean-filled cakes.
Using a bamboo steamer set in a pan of simmering water, steam the rice cakes in batches until cooked through, about 25 minutes. Transfer to a platter and brush with sesame oil. Serve with honey for dipping.