Cut chicken thighs into 1-inch pieces. In a large skillet or wok, heat 15 ml of vegetable oil over medium-high heat. Brown the chicken pieces in batches, ensuring not to overcrowd the pan. Remove chicken and set aside.

Add the remaining 15 ml of vegetable oil to the skillet. Add minced ginger, garlic, and crushed red pepper flakes. Sauté for about 30 seconds until fragrant.

Pour in orange juice, brown sugar, ketchup, rice vinegar, soy sauce, and 60 ml water. Stir well to combine and bring the mixture to a simmer.

In a small bowl, whisk together cornstarch and 30 ml of water to create a slurry. Gradually whisk the slurry into the simmering sauce until it thickens to your desired consistency.

Return the browned chicken pieces to the skillet. Toss to coat evenly with the thickened sauce. Cook for another 2-3 minutes, allowing the chicken to heat through and absorb the flavors.

Garnish with toasted sesame seeds and sliced scallions before serving.