Add oil to skillet; sauté ginger and garlic until fragrant. Add sweet potatoes and onions; stir fry until vegetables are tender crisp, about 3 minutes. Add chicken stock, chicken and stir-fry sauce; toss to coat. Season with salt, pepper and soy sauce to taste.
Divide rice into 4 to 6 individual serving bowls, top with sweet potato chicken mixture. Garnish with sesame seeds and green onions.