In a shallow bowl, add the chicken, chili powder, garlic, ¼ teaspoon salt, lemon or lime juice, and water. Toss to completely coat all the chicken. Set aside while you slice all the vegetables.
In a large skillet, heat the oil over medium high heat. Add the sliced onions and peppers, and stir fry for about 5 minutes. Season with the remaining ¼ teaspoon salt.
Push the vegetables to the sides of the skillet and add the chicken along with the marinade. Stir fry the chicken for about 5 minutes.
Then stir everything together, and stir fry for another 3 minutes until the marinade liquid has thickened and the chicken is done.