Slice beef into thin strips against the grain. Season with salt and pepper and let sit for 15 minutes.
Whisk cornstarch, Kosher salt, and black pepper in a large bowl. In another bowl, beat the eggs. Dip beef strips in egg, then coat with cornstarch mixture.
Heat 2 inches of peanut or vegetable oil in a heavy-bottomed pot or deep fryer to 350°F (175°C).
Fry coated beef strips in batches for 3-4 minutes until golden brown and crispy. Remove and drain on paper towels.
Whisk together rice vinegar, light soy sauce, dark soy sauce, sugar, honey, sweet chili sauce, and red pepper flakes in a large mixing bowl.
Heat 1 tablespoon oil in a large skillet or wok over medium-high heat. Stir-fry onion, carrot, red chili pepper, garlic, and ginger for 3-4 minutes until tender-crisp.
Add fried beef to skillet with vegetables. Pour sauce over and toss to coat and heat through for 2-3 minutes.
Transfer to serving platter and garnish with toasted sesame seeds and sliced scallions. Serve immediately.