To make the marinade, combine the soy sauce, sugar, chili paste, and cornstarch in a medium bowl and whisk until smooth. Add the chicken pieces to the bowl and toss to coat. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow the chicken to marinate.

When the chicken is ready, heat the vegetable oil in a large skillet over medium-high heat. When the oil is hot, add the chicken pieces to the skillet in a single layer. Fry the chicken for 3-4 minutes on each side, or until it is cooked through and golden brown.

Remove the chicken from the skillet and place it on a plate lined with paper towels to drain any excess oil. Season the chicken with salt and pepper to taste. Serve the firecracker chicken hot, with your favorite dipping sauce, such as sweet and sour sauce or hot mustard. Enjoy!