In a medium-sized saucepan, combine the water, soy sauce, honey, Sriracha, and minced garlic. Place the saucepan over medium heat and bring the contents to a boil, stirring intermittently.
In a separate small bowl, whisk together 2 tablespoons of cornstarch with 2 tablespoons of cold water until fully dissolved. Gradually stir the slurry into the saucepan. Continue cooking, stirring frequently, until the sauce thickens to your desired consistency. Once thickened, reduce the heat to low.
Place the chicken pieces in a large zip-top plastic bag. Add ½ cup of cornstarch to the bag, seal it tightly, and shake until each piece is evenly coated.
Heat a large non-stick skillet over medium heat and lightly oil the surface. Arrange the coated chicken in a single layer and cook for several minutes on each side until thoroughly cooked and golden brown. Work in batches if necessary to avoid overcrowding the pan.
Once all chicken is cooked, remove the skillet from the heat. Pour the prepared honey garlic sauce over the chicken and toss gently until the pieces are well-coated. Taste and adjust seasoning with salt and pepper if needed.
Serve hot over white rice. Garnish with sesame seeds and chopped green onions if desired.