In a shallow dish, beat egg with 2 tablespoons soy sauce.
Add chicken and toss to coat. Let sit 5–10 minutes.
Sprinkle cornstarch over chicken and toss evenly.
Heat oil and fry chicken in batches (4–5 minutes per batch) until golden and cooked through. Remove and drain.
In a saucepan, combine remaining soy sauce, water, honey, ketchup, sesame oil, lime juice, and salt. Simmer 2–3 minutes.
Add cornstarch slurry (1 tsp cornstarch + 1 tbsp water) and cook until thickened (1–2 minutes).
Toss chicken in sauce.
Garnish with sesame seeds and green onions. Serve immediately.