In a 10-inch sauté; pan, heat butter and olive oil over medium high heat. Coat frog legs in seasoned flour, shaking off all excess. When butter is hot, sauté frog legs 2 to 3 minutes on each side. Add onions and garlic. Saute 3 to 5 minutes or until vegetables are wilted. Add tomatoes and cook 2 to 3 additional minutes. Deglaze with white wine, then add chicken stock. Bring to a rolling boil. Then reduce to simmer and cook until frog legs are tender, 5 to 7 minutes. Sauce should be slightly thickened because of the flour in the skillet. Add green onions and season to taste using salt and pepper. Additional stock may be needed to return a sauce-like consistency.