Creating Crispy Chilli Beef is simple if you follow these clear instructions:

1. Marinate the Beef: In a bowl, combine beef strips, soy sauce, rice vinegar, sugar, sesame oil, and chili sauce. Let marinate for at least 15 minutes.
2. Prepare the Coating: Spread cornstarch on a plate. Remove the beef from the marinade and coat each piece with cornstarch. Shake off excess.
3. Heat Oil: In a wok or large frying pan, heat vegetable oil over medium-high heat.
4. Fry the Beef: Add coated beef strips in batches, frying until golden brown and crispy (approximately 3-4 minutes). Remove and drain on paper towels.
5. Stir-Fry the Vegetables: In the same pan, add minced garlic and ginger. Sauté for 30 seconds, then add bell pepper and onion, stir-frying slightly until tender-crisp.
6. Combine with Beef: Return the crispy beef to the pan, tossing it with the vegetables.
7. Add Sauce: Pour any remaining marinade into the pan. Stir-fry everything together for about 1-2 minutes until well coated and heated through.
8. Garnish: Sprinkle with chopped spring onions and sesame seeds for extra flavor and presentation.
9. Serve Immediately: Plate the dish while it’s hot and enjoy!

Following these steps will guide you in crafting an incredible meal full of textures and tastes!