To prepare filling. Dry fry sesame seeds in a clean pan over low heat till fragrant, about 30 seconds.
Grind sesame seeds to a fine powder.
Mix together the ground sesame seeds, pork fat and sugar till smooth.
Chill well in refrigerator till solid, about 30 minutes.
To prepare skin. Mix together the ingredients. Knead into a smooth dough, then divide into 20 equal pieces.
Shape each piece of dough into a ball.
Flatten each and put 1 piece of filling in the centre.
Gather up the edges and seal. Roll into smooth ball again.
Bring water to the boil. Stir in sugar till dissolved.
Add sesame rice balls and cook 5 minutes till they rise to the surface.
Dish up syrup and balls into individual bowls and serve hot.
