Tony's Pizza NapoletanaA pizza oven in Naples.The pizza gods were smiling over North Beach this weekend. On Saturday, Bay Area favorite pizza guy Tony Gemignani opened Tony's Pizza Napoletana (1570 Stockton at Union). Die-hard fans know Gemignani and his pie-making skills from his Pyzano's outpost in Castro Valley and frequent media appearances (hello, Food Network!) and public events. Being a nine-time world pizza champ gives the enthusiastic Gemignani true pizza cred: When he puts on a show of