In a city notorious for gun violence, President Barack Obama will continue his push for tougher laws on Friday amid questions about whether a key proposal to ban semi-automatic weapons that mimic military assault rifles would address the issue of handguns involved in most killings. Obama will speak at Hyde Park Academy High School in Chicago, the city where Hadiya Pendleton, 15, was killed by gunfire last month. She had just returned from Washington, where she had taken part in inaugural activities. Obama headed to his hometown after a White House ceremony to award the Presidential Citizens Medal -- the nation's second-highest civilian honor -- to 18 people. They included posthumous honors for six educators killed along with 20 first-graders in December's Connecticut school massacre. He hugged family members of the slain teachers and administrators from Sandy Hook Elementary School in presenting the medals, saying: "We could not be more grateful…