Creating Spicy Stir-Fried Mongolian Chicken is straightforward if you follow these simple steps:

1. Prepare the Chicken: Slice the chicken thighs into thin strips and set aside.
2. Marinate: In a bowl, mix soy sauce, hoisin sauce, chili paste, and cornstarch. Add the sliced chicken and let it marinate for 10 minutes.
3. Heat Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Cook Chicken: Add the marinated chicken to the skillet and cook for 5-7 minutes, or until browned and cooked through. Remove the chicken from the skillet and set aside.
5. Sauté Vegetables: In the same skillet, add the sliced bell peppers, onion, garlic, and ginger. Stir-fry for about 3-4 minutes until the vegetables are tender-crisp.
6. Combine: Return the chicken to the skillet and pour in the sesame oil. Mix everything well, ensuring the chicken and vegetables are coated in the sauce.
7. Garnish: Remove from heat and garnish with chopped green onions and sesame seeds.
8. Serve: Transfer to a serving platter and enjoy immediately.

These simple steps will guide you in creating this wonderful dish effortlessly.