Start by cutting chicken thighs into evenly-sized 1-inch pieces. Try to keep them uniform so they’ll cook at the same rate. If you spot any tough bits of fat or gristle, go ahead and trim those off.
Set up your dredging station: In one bowl, whisk together 3 eggs until well blended. In another bowl, add 1 cup cornstarch. Line a large plate with paper towels and keep it nearby.
Working in batches, dip chicken pieces in egg, then roll in cornstarch until completely coated. I like to use one hand for wet ingredients and one for dry to avoid creating gunky fingers. Place the coated pieces on a plate while you finish the rest.
While you’re coating the chicken, make your sauce. In a bowl, whisk together soy sauce, rice vinegar, honey, and brown sugar until the sugar starts dissolving. Add your minced garlic and ginger, sesame oil, and water. In a small separate bowl, mix 2 tablespoons cornstarch with just enough cold water to make a slurry (about 2-3 tablespoons). Stir this into your sauce mixture until well combined.
Heat vegetable oil in a large, heavy-bottomed skillet over medium-high heat. You want it hot but not smoking – test by dropping a tiny bit of cornstarch in; it should sizzle immediately but not burn.
Fry the chicken in batches – don’t crowd the pan or the temperature will drop and your chicken won’t get crispy. Each batch should take about 4-5 minutes, turning pieces halfway through. You’re looking for a golden brown color and a crispy coating. Remove to your paper-towel lined plate.
Once all chicken is fried, pour out all but about 1 tablespoon of oil from the pan. Return pan to medium heat and pour in your sauce mixture. It will start bubbling pretty quickly – stir constantly as it thickens. This takes about 2-3 minutes, and you’ll know it’s ready when it coats the back of your spoon and has a glossy sheen.
Add your fried chicken pieces back to the pan and gently toss to coat every piece with sauce. Keep tossing for about 1 minute to heat everything through and let the sauce really stick to the chicken.
Sprinkle with toasted sesame seeds while everything’s still hot and sticky – they’ll adhere better this way. Finish with a scatter of sliced green onions.