Toss the chicken with the onion and garlic and marinate for at least 30 minutes in the refrigerator.

 

Whisk the egg, water, cornstarch, salt and pepper together in a medium bowl just until cornstarch is moist.  Do not over mix.

 

Over medium heat, heat at least an inch of oil in a deep heavy saucepan.  Using long chop sticks or tongs, dip one chicken piece at a time in the cornstarch mixture and carefully place it in the hot oil.  Repeat until the pan is almost full but the chicken pieces aren't touching.  Cook until crispy and golden brown,  usually about 10 minutes.  To check if its cooked through take out the largest piece and cut to see that the juices run clear.  Place the pieces on a plate lined with paper towels.  Repeat until all the pieces are cooked.

 

Mix the Chili paste, sugar, catsup, sesame seeds and lemon juice in a large bowl.  Add the fried chicken and carefully turn to coat all the pieces with the seasoning.  Serve immediately