Cut chicken into 1-inch cubes. Add to a large bowl with cornstarch, salt, and pepper. Toss to coat.
Deep fry chicken in batches at 375 in a deep frier or over medium high heat in a wok. The chicken will be done when it starts to turn lightly golden brown on the outside. Make sure the internal temperature of the chicken pieces reaches 165 degrees. Remove chicken pieces from pan or fryer and allow to drain on paper towels.
Meanwhile, in a large saucepan combine 1 cup water, lemon juice, orange juice, rice vinegar, and soy sauce. Whisk ingredients together over medium heat for a few minutes.
Stir in brown sugar, orange zest, ginger garlic, and onion. Bring to a boil. Combine 3 tablespoons of cornstarch with ¼ cup of water and mix thoroughly. Slowly stir cornstarch mixture into sauce until it thickens.
Place fried chicken in a large bowl and pour sauce over the top. Add pineapple tidbits. Toss gently to coat.
Serve with rice and garnish with green onions and sesame seeds.