In a food processor, combine the chicken, lemon grass, ginger, garlic, chilli, coriander, soy sauce and sesame oil. Pulse until thoroughly mixed and chicken is minced.
Separate all of the wonton wrappers, and lay them out on a clean surface. Set a bowl of water to the side to dip your fingers. Place about 1 teaspoon of the chicken mixture onto the center of each wrapper. Wet the edges by dipping your fingers in water, and wiping the edge of each wrapper. Fold over into triangles, and press to seal. Take the two opposing points of the triangle, and fold around to join together.
Heat the oil in a deep-fryer or deep pan to 185 degrees C. Deep-fry several wontons at a time, turning as needed, until lightly browned. Remove to drain on paper towels. Serve while hot.