Measure rice flour in a medium-size bowl. Make a well in the center of flour and pour boiling water into well, stirring with chopsticks or a fork until dough is evenly moistened. Add cold water and stir until dough forms a ball. On a lightly floured surface, knead dough for about 5 minutes or until smooth and shiny. Cover with a damp cloth and let rest for 10 minutes. Roll dough into a 12-inch-long cylinder. Cut cylinder crosswise into 1-inch pieces.