Days after President Barack Obama’s historic visit, the leaders of Cuba’s Communist Party are under highly unusual public criticism from their own ranks for imposing new levels of secrecy on the future of social and economic reforms. After months of simmering discontent, complaints among party members have become so heated that its official newspaper, Granma, addressed them in a lengthy front-page article Monday. It said the public dissatisfaction over the lack of open discussion before the upcoming Communist Party congress next month is “a sign of the democracy and public participation that are intrinsic characteristics of the socialism that we’re...