Cut boneless skinless chicken breast or thighs into bite-size pieces. Sprinkle with salt and toss to coat.
Place flour and cornstarch in a shallow dish or pie plate. Add a generous pinch of salt. Stir.
Whisk eggs in shallow dish. Dip chicken pieces in egg mixture and then flour mixture. Place on plate.
In a medium pot, add pineapple juice, sugar, vinegar, soy sauce, ginger, garlic, and red chili flakes. Heat for 3 minutes.
In a small bowl, whisk 1 Tablespoon of cornstarch with 1 Tablespoon of water to form a paste. Add to pineapple sauce and whisk together.
Continue to cook for 5 minutes, until the mixture begins to thicken. Once the sauce is thickened, remove from heat and add ½ cup of pineapple (if desired). If using snow peas, add them to the sauce.
Heat oil in a heavy-bottomed pot over medium-high heat. Let the oil heat up to 350 degrees.
Once the oil is ready, in batches, cook chicken for about 2-3 minutes, turning often, until light golden brown. Repeat with remaining chicken.
Remove from oil and drain on a paper towel-lined plate.
Toss crispy chicken with the sweet pineapple sauce. Top with fresh pineapple pieces and green onions. Serve immediately.
