For the chicken, finely chop the chilli, lemon grass, ginger and garlic and crush in a pestle and mortar with the peppercorns, coriander, lime and sunflower oil to make a paste. Score each chicken piece diagonally with a sharp knife. Rub the paste into the meat with you fingers. Place in the fridge to marinate: overnight is best, but a few hours is fine. If you are planning on having a BBQ you can dice your chicken up into smaller cubes or use chicken goujons.