
In a wide skillet over medium heat, heat oil. Add onions and garlic and cook until softened.
Add chicken and cook, stirring occasionally, until lightly browned and juices run clear.
Add tamarind powder and stir until chicken wings are fully coated.
Add water and soy sauce. Bring to a boil.
Lower heat, cover, and continue to cook until chicken is tender and sauce is reduced.
Season with salt and pepper to taste.
Transfer to a serving platter and garnish with chopped green onions and toasted garlic if desired. Serve hot.