Stir together soy sauce, vinegar, sesame oil, and 2 tbsp water in a bowl; set aside
Place chicken in medium bowl. Season with salt and pepper, sprinkle with cornstarch; toss lightly to coat
Heat 2 tbsp vegetable oil in a large wok or nonstick skillet over medium-high. Cook chicken, tossing occasionally, until golden brown and nearly cooked through, about 6-8 minutes. Add red onion, garlic, ginger, Aleppo pepper, and remaining 2 tbsp oil. Cook, tossing, until vegetables are softened, about 2 minutes
Add corn and cook, tossing often, until tender, about 3 minutes
Stir in sauce mixture and cook, tossing often, until reduced to a glaze, about 2 minutes. Taste and season with salt and pepper as needed
Serve with rice