Using a sharp kitchen knife, slash the chicken legs several times through to the bone. Chop off the knuckle end and discard.
To make the marinade, place the cashew or macadamia nuts in a food processor and grind until fine (or use a pestle and mortar to grind them).
Add the chopped shallots or onion, garlic, chilies and lemongrass and blend. Add the remaining marinade ingredients and blend again.
Spread the marinade over the chicken and leave for up to 8 hours in the refrigerator. Cook the chicken on a medium grill for 25 minutes, basting and turning occasionally. Garnish with radishes and cucumber and serve on a bed of Chinese cabbage.