Mix flour, chile, salt and pepper and coat oxtails well. In a hot stock pot, coat bottom with oil and sear oxtails until all sides are browned. Pull out oxtails and wipe out stock pot. Saute onions, fennel, celery, carrots, garlic, ginger and lemon grass. Deglaze with wine and reduce. Add tomatoes, soy, thyme and bay. Add water to completely cover meat. Check for seasoning: the broth should taste well seasoned. Bring to boil then simmer on low heat for 3 hours. The meat should fall off of the bone. Remove oxtails and reduce sauce by 20 percent. Using a hand blender, puree sauce. Check for seasoning. Serve on top of polenta.
PRESERVED LEMON POLENTA: In a saucepan, saute shallots and ginger in 1 tablespoon of butter. Add polenta, lemons, stock, salt, pepper and butter. Check for seasoning. Stir well and cover tightly. Bake in 400 degree oven for 1 hour. A crust will form. Break through crust for polenta.