In a large mixing bowl, combine chicken thighs, water, baking soda, and salt. Mix until the water is absorbed, then add eggs and mix well. Add cornstarch and oil, mixing until combined.

Heat about 2-3 inches of oil in a wok or tall pan until it reaches 375°F.

In another bowl, combine ketchup, water, sugar, vinegar, cornstarch, soy sauce, and dark soy sauce.

Carefully place marinated chicken pieces into the hot oil, working in batches to avoid overcrowding. Fry for 4-5 minutes until cooked through; then remove and drain.

Return the chicken to heated oil for another 5-6 minutes or until golden brown and crispy. Drain on paper towels.

In a wok over medium heat, add a small amount of oil, then the white parts of the green onions. Stir-fry until fragrant, then add the prepared sauce and stir until thickened.

Toss the fried chicken in the sauce until well coated. Serve immediately with rice, garnished with sesame seeds and green onion tops.