Mix the water and cucumber in a pitcher. Refrigerate up to 1 hour before serving.
Rise the rice with cold water and drain thoroughly. In a saucepan, add the recommended amount of water and cook according to the directions on the package.
To make the sauce, whisk together the sugar, brown sugar, apple cider vinegar, ketchup, soy sauce, and garlic in a small bowl. Set aside.
Mix the chicken pieces and cornstarch in a bowl until all the pieces are well coated. Dip into the egg, then into the flour before adding to the hot oil.
Heat the oil in a skillet over medium heat. Cook the chicken for 2-3 minutes, until cooked through and crispy to an internal temperature of 160 degrees using a thermometer.
Remove to a baking sheet and continue cooking all the chicken pieces.
Add 1 to 2 teaspoons of the oil used to fry the chicken to a saute pan on medium heat. Add the bell peppers, onion, and pineapple (if using) and cook for 5 to 7 minutes, until tender. Add the sauce in and stir, bringing to a simmer until the sauce has thickened to a syrup consistency.
Stir in the chicken pieces.
Finish the rice: Fluff with a fork and season with salt and pepper to taste.
Serve the chicken over rice with fortune cookies and cucumber water.