Napa welcomes a new restaurant to its downtown food and wine roster next week when chef Sean O’Toole returns with a contemporary American eatery in the space that once housed Ubuntu. While it is not his first restaurant, it is the first culinary operation where he is not only executive chef but also proprietor. A few years ago, O’Toole crafted the menus for the restaurant in Yountville’s Bardessono hotel, a post he held for two years.