Put sliced chicken in a bowl and mix with the 5 spice powder, salt, pepper, chilli powder, soy sauce and 1 tablespoon corn flour.
Mix together all the ingredients for the sauce and set close to the stove.
In another bowl, mix remaining corn flour and flour. Add chicken and toss to combine. Put coated chicken in a colander and shake to remove excess flour.
Heat oil in a large skillet and cook chicken in two batches. Remove chicken with a slotted spoon. In the same skillet cook ginger and garlic until fragrant and soft. Add peppers and onion. Cook for a minute or so to soften slightly. Add chicken back to the skillet and pour over the sauce. Bring to a simmer and mix. As soon as sauce is thick and coats chicken remove from heat. Mix in pineapple chunks and sprinkle with the spring onion. Serve with rice.