Cut 500 grams of boneless, skinless chicken breasts into thin strips and marinate them in a mixture of 2 tablespoons lime juice, 1 tablespoon oil, 1 teaspoon cumin powder, 1 teaspoon paprika, 1/2 teaspoon red chili powder, 1/2 teaspoon black pepper, and salt to taste. Let it marinate for at least 30 minutes.
Thinly slice 1 large onion and 2 bell peppers (preferably different colors) and set aside.
Heat 2 tablespoons of oil in a large pan over medium-high heat. Add the marinated chicken and cook for 5-7 minutes, stirring occasionally, until the chicken is cooked through. Remove the chicken from the pan and set aside.
In the same pan, add a little more oil if needed, and sauté the sliced onions and bell peppers for 3-4 minutes until they are slightly softened but still have a crunch.
Add the cooked chicken back to the pan and mix well with the onions and bell peppers. Cook for another 2 minutes to blend the flavors.
Warm 6-8 tortillas on a tawa or in a microwave for a few seconds. Place the chicken fajita mixture onto the center of each tortilla, and add your choice of toppings like sour cream, salsa, and grated cheese. Fold the tortilla and serve immediately.