LOS ANGELES—A 20-year-old West Hills man who started a fire that caused substantial damage to a Santa Monica sushi restaurant last year pleaded guilty this week to a federal charge. Micah Tillmon entered his plea to possession of an unregistered destructive device, in particular an incendiary device, a charge that carries a sentence of up to 10 years in federal prison, according to the U.S. Attorney’s Office. At sentencing on Dec. 6, Tillmon is also expected to be ordered to pay restitution in the amount of $500,000, court papers show. The defendant is also facing multiple looting and commercial burglary charges in a complaint filed by the Los Angeles County District Attorney’s Office. However, the federal case is proceeding first. Authorities said Tillmon used a homemade incendiary device to set fire to the Sake House at the corner of Santa Monica Boulevard and Fourth Street on May 31, 2020, during …