Remove skins and bones from chicken and use them to prepare chicken stock. Cube chicken. Heat oil in a large skillet; saute chicken and garlic until browned. Add broth, ginger and salt; simmer 1 hour or until chicken is tender. Soak long rice in warm water for 30 minutes; cut into 2 inch pieces. Add long rice and mushrooms to chicken; simmer 15 more minutes. Sprinkle with green onions just before serving.