Add rice, butter, salt and water to a rice cooker or pot on the stove and cook until liquid has absorbed.
Add eggs to a bowl, then mix cornstarch and flour together in another large bowl. Dredge chicken in egg mixture, then toss in flour mixture.
Heat a large skillet over medium-high heat and add sunflower oil. When lightly smoking, add chicken and cook for 3-4 minutes per side until golden brown. Add chicken to a paper-towel lined plate to drain oil. Season with salt and set aside.
Meanwhile, whisk orange juice and cornstarch together in a large bowl until there are no lumps. Mix in hoisin sauce, sweet chili sauce, soy sauce, lemon juice, minced garlic and sriracha, stirring until well combined. Microwave, covered, for 1 minute until sauce thickens.
Toss cooked chicken in the bowl with the sauce, then divide cooked rice among plates. Top with chicken, garnishing with green onions and sesame seeds. Serve and enjoy!