Combine the sauce ingredients in a large bowl or glass measuring cup. Whisk well.
Cut the chicken into 1 1/2 inch pieces and transfer to a large bowl. Add cornstarch, salt & pepper; toss to coat.
Heat oil in a large skillet over medium-high heat. Add the chicken and pan fry 6-8 minutes, until golden brown. Remove from pan and place on a wire rack or paper towel-lined plate.
Add the sauce to the pan; heat over medium-high heat, whisking often, until thickened and bubbly.
Add the chicken back into the pan with the sauce. Stir to coat.
Remove from heat. Garnish with green onions, sesame seeds, red pepper flakes, and orange zest as desired.
Enjoy on its own or over rice.