1. In a bowl, combine cornstarch, water, and sherry and stir well. Add chicken and mix gently to coat evenly with marinade. Set aside for 20 minutes.

2. In a small bowl, combine chicken stock, soy sauce, salt, and sugar and stir well.

3. Heat a wok or large deep skillet over high heat. Add oil and swirl to coat pan. Add garlic, jalapeno peppers, and ginger and toss well, until garlic and ginger are fragrant, about 15 seconds.

4. Add chicken mixture, quickly spread into a single layer and cook, undisturbed, until edges turn white, about 1 minute. toss well and cook for 1 minute more. Add bell peppers and toss well. Reduce heat to medium.

5. Add chicken stock mixture and cook, until chicken is longer pink inside and peppers are tender-crisp, 1 to 2 minutes more. Transfer to a serving platter. Serve hot or warm.

Tips:
To chop jalapeño peppers, cut off stems and halve each pepper lengthwise, discarding seedy portions and most of the seeds. chop lengthwise into thin strips and then crosswise to make small bits.

To prepare pepper strips, halve each pepper lengthwise and discard stem section and seeds. Cut off the rounded top and bottom portions and reserve for salad or other dishes. Cut enough of the remaining portion of each pepper into slender strips about 1 1/2 inches (4 cm) long.