Step 1: Pat the chicken pieces dry with paper towels. Season generously with salt and black pepper.
Step 2: Heat a large skillet or wok over medium-high heat. Add olive oil. Once hot, add the chicken pieces in a single layer, working in batches if necessary to avoid overcrowding. Cook for 3-4 minutes per side until golden brown and cooked through. Remove cooked chicken from the pan and set aside.
Step 3: Reduce heat to medium. Add minced garlic and grated ginger to the pan. Sauté for 30-60 seconds until fragrant, being careful not to burn them.
Step 4: Pour in the sweet chili sauce, soy sauce, and rice vinegar. Bring the mixture to a gentle simmer, stirring. If you prefer a thicker sauce, whisk together cornstarch and cold water to create a slurry, then stir it into the simmering sauce. Cook for 1 minute until thickened to your desired consistency.
Step 5: Return the cooked chicken to the pan, tossing gently to coat all pieces evenly with the sweet chili sauce. Cook for another 1-2 minutes, allowing the chicken to absorb the flavors. Garnish with sesame seeds and chopped green onions before serving.