Paul Stallings ’s trendy Hotel on Rivington has been a fixture in the Lower East Side.  Stallings, a former Wall Street lawyer, opened the area’s premier boutique hotel in 2004.  Bernstein Redo, P.C. has represented the Rivington since it opened.  Then on the cutting edge, it was transformative of the neighborhood. The 21-story glass structure has had a number of restaurants operate within the hotel over the past decade. As reported this past weekend, now it is being sold to the Kushner family. This is the first venture into the hospitality business for the Kushner’s.