Whisk sweet chili sauce, soy, 1½ tbsp lime juice, rice vinegar, honey, garlic, ginger, red pepper, and 1 tbsp oil. Reserve 1/4 cup for glazing.
Pat chicken dry, season with salt and pepper, then coat with the remaining marinade. Chill 20–30 minutes.
Preheat grill to medium-high. Clean and oil grates with the vegetable oil.
Grill chicken 5–6 minutes per side until charred in spots and 165°F inside. Brush with reserved glaze during the last 2 minutes.
Rest 5 minutes. Sprinkle green onions and sesame, then drizzle the remaining 1 tbsp lime juice. Serve hot.