In a Ziploc bag, combine the Chinese cooking wine, sesame oil, sugar, salt, soy sauce and tomato sauce. Add pork tenderloin and marinate in a fridge for at least two hours and up to 6 hours for best results.
Heat a wok or a cast iron pan over medium heat. Add the pork and the marinade, and cook and bring to gentle boil. Cover and simmer, occasionally stirring, for about 5-7 minute. Flip the meat and continue simmering for another 5-7 minutes, until internal temperature of the meat reaches a minimum safe temperature of 145F. Remove the meat from the pan and set aside.
To make the sauce, dissolve tapioca starch in 1 cup of water and add to the pan with the marinade leftovers after meat simmering. Bring to boil and simmer until the sauce thickens.
To serve, slice the pork about 1/4 inch thick, place on top of rice bed and dress with the sauce. Garnish with slices of cucumber, scallions and fresh coriander leaves.