In a medium bowl, combine sliced chicken with egg white, cornstarch, salt, and pepper until well-coated. Allow the chicken to marinate for 10-15 minutes.

Heat a large skillet or wok over medium-high heat, adding oil until shimmering. Carefully add the marinated chicken in batches and fry for about 4-5 minutes per side until golden brown and crispy. Transfer the chicken to a plate lined with paper towels.

In the same skillet, reduce the heat to medium and add sesame oil. Sauté minced garlic, grated ginger, and dried chilies for 1-2 minutes until fragrant.

Stir in the ketchup, soy sauce, chili garlic sauce, vinegar, and sugar. Allow the sauce to simmer for 2-3 minutes and adjust with a splash of water if too thick.

Add the crispy fried chicken back into the skillet, tossing gently in the sauce to coat evenly. Simmer for an additional minute.

Remove from heat and transfer to a serving platter. Garnish with green onions and sesame seeds. Serve immediately.