I ate a version of this dish at a party in Singapore and liked it so much that I made it at home. These easy-to-make, two-bite wraps are great as an accompaniment to serve with drinks: make a platter of them and hand them around to your guests. They should be eaten within 10 minutes, or else they will fall apart once the wrapper gets soggy. Be sure to use kimchi that's not too aged, or the flavours will be too pungent.
Buy a boneless, slightly fatty piece of siu yuk (Chinese roast pork) from a siu mei (roast meat) shop - the belly meat is best, but avoid the breast because it's too dry.
The spring roll wrappers (also called egg roll wrappers and spring roll pastry) should be square and made of wheat flour, not the very thin rice paper wrappers that need to be dampened with water and which are used for Vietnamese spring rolls. They're usually sold in the frozen products section of supermarkets.
If the siu yuk is cold and the skin is soft, rather than crisp, heat it by putting it skin-side-up on a tray and placing in an oven that’s pre-heated to 180ºC (350ºF). Heat for 10 minutes then cool to room temperature. Use a serrated knife to cut the siu yuk in half lengthwise, then slice each piece 5mm (¼in) thick – you should have 40 pieces. (A tip for tidier slices: cut the siu yuk upside-down, so the skin side is on the cutting board.)
Drain the kimchi in a colander for about 5 minutes. Put the drained kimchi on a double layer of paper towels and squeeze out the excess moisture. Roughly chop the kimchi.
Put the hoisin sauce, oyster sauce and sesame oil in a small pan, bring to the boil, then lower the heat and simmer for about 5 minutes.
Wrap the spring roll wrappers in a doubled-up layer of dry kitchen cloth. Microwave briefly, or until warmed through. (If you don’t have a microwave, heat them one-at-a-time on a stovetop griddle placed over a medium flame: heat each wrapper for a few seconds on each side, then stack them, keeping them warm by wrapping them in a doubled-up layer of dry kitchen cloth.) Cut each wrapper into four smaller squares and keep them warm. (If they become stiff when working with them, heat them again.)
Lay several of the wrappers side-by-side on a work surface, with one of the corners facing you. Use a spoon to smear a small amount of the sauce on the diagonal, from one corner to the other. Lay a piece of pork in the centre of the wrapper and top with some of the kimchi. Fold up the near corner of the wrapper towards the centre, then fold over the side corners and roll it to securely enclose the filling. Lay the wrap on a platter and finish making the others. Makes 40 pieces.