Ten Tables founder Krista Kranyak is expanding her restaurant empire. Kranyak announced via Twitter this week that she’s opening a place in Jamaica Plain called GrassFed. The new burger bar will be in business Feb. 1 in the space formerly occupied by Bon Savor. (The couple who owned Bon Savor put the location up for sale after they traveled to Colombia but were unable to return because of visa problems.) Kranyak opened the first Ten Tables restaurant in 2002, followed by locations in Cambridge and Provincetown.