A 13-year-old boy was killed and a 12-year-old was critically injured after a motorcycle they were riding was struck by a truck in Fresno late Friday night, authorities said. Police responded around 10:42 p.m. to multiple reports of a crash at Bullard and Palm avenues. Officers arriving at the scene found the two juveniles on the ground and began medical care before both were taken to Community Regional Medical Center, Fresno police said. The 13…