Heat oven to 220C/fan 200C/gas 7. In a roasting tray, toss the wings with the soy sauce, 125g of the sugar, 2 tbsp of the vinegar and some cracked black pepper. Roast for 40 mins, turning occasionally until lacquered.
Meanwhile, bring the remaining sugar and vinegar to the boil for about 1 min, until the sugar dissolves. Leave to cool, then toss with the cucumber ribbons. Serve the sticky wings with the cucumber and some boiled rice.