Rinse and soak lala (textile venus clams) in water for 30 minutes to allow them to release as much grit trapped inside the clam. Drain.
Bring a large wok of water to a boil. Add lala and blanch for 1 minute. The lala should open up and whatever remaining grit inside the shell will drop into the boiling water. Transfer blanched lala with a strainer into a bowl. Discard the water and rinse the wok.
When cool enough to handle, separate and remove one half of the shell where the meat is not attached to.
Heat vegetable oil in the wok. Add spice paste and stir fry for 3 to 4 minutes until fragrant.
Stir in the sugar and add the prepared lala. Continue to stir fry for another 2 minutes until lala is heated through and coated with sauce. Turn off stove. Transfer to a serving dish.
Garnish with cilantro and serve immediately with steamed rice.