1. Mix pork with marinade ingredients to coat evenly in a mixing bowl. Marinade for at least 30 mins or up to 4 hours in the refrigerator.
2. In another bowl, mix well cornstarch and tapioca flour.
3. Heat oil on high heat in a wok. Coat pork cubes with mixture of corn and tapioca flour. Gently lower into hot oil and fry for 3-5 mins or until they are golden brown. Remove pork pieces and drain over wire rack.
4. For the sauce, heat oil on medium high heat in a wok. Sauté onions until soft, add sauce, cucumber and pineapple. Stir to mix well. Remove from heat.
5. Arrange pork pieces on a serving plate and pour Sweet and Sour sauce mixture over meat pieces. Ready to serve.