Put the chicken legs in a large bowl with the soy sauce, maple syrup, two tablespoons of oil, the lime juice and a half-teaspoon of salt, then set aside to marinate for an hour, or in the fridge overnight.
Heat the oven to 210C (190C fan)/WEB 425F/gas 7. Tip out the contents of the chicken bowl on to a large oven tray lined with greaseproof paper, arrange the chicken skin side up and pat the skin dry. Pour over the remaining tablespoon of oil, then roast for 40-45 minutes, until the juices run clear and the skin is crisp.
Meanwhile, in a bowl, whisk all the satay sauce ingredients with a tablespoon and half of water, until smooth, and in a second bowl mix all the sambal ingredients with half a teaspoon of salt.
Transfer the chicken and all the liquid from the tray to a large platter. Arrange the lettuce, cucumber, sambal, lime wedges and the bowl of satay sauce alongside, and serve.