Make the marinade: put the onion, garlic, oil, sauce and seasonings into a food processor and process until smooth. Pour the marinade into a Pyrex or other measuring cup; fill with water to reach one cup.
Cut chicken breasts into bite-sized pieces. Put into a resealable plastic bag; pour marinade over the chicken. Seal. Refrigerate for at least an hour. (Or overnight.)
Prepare a wok or heavy skillet; heat it and add olive oil. Add enough chicken to cover the wok or skillet in a single layer. Cook until no pink remains in the middle. (We like our chicken almost crispy.)
Another option: marinate the whole breast (or thigh), cook and then cut into pieces. I did this for awhile but we like the taste and texture of cutting the chicken into bite-sized pieces, marinating, then cooking.