In a large mixing bowl, combine flour, sugar, salt, and yeast. Add warm water and vegetable oil. Mix until a dough forms.
Knead the dough on a floured surface for about 10 minutes until smooth and elastic. Place in a greased bowl, cover, and let rise until doubled, about 1 hour.
Preheat oven to 375°F (190°C). Punch down the dough and divide into 8 equal pieces. Shape into rolls and place on a baking sheet.
For the topping, mix rice flour, sugar, yeast, and salt in a bowl. Add warm water and stir to combine. Let sit for 15 minutes.
Spread the topping mixture over each roll. Bake for 20-25 minutes or until golden brown and crunchy.