PHNOM PENH — The really challenging thing is trying to teach his countrymen how to eat a hamburger — a culture clash that is more than culinary as he tries to fit himself, like a lost piece in a puzzle, back into the land of his birth.

His Cambodian name is Chenda Im, but after more than 30 years as a refugee in the United States, he goes by Mike, and he is the founder, owner, manager, cook and pitchman of Mike’s Burger House, which he opened on the lot of a gas station here after his return four years ago.

“I’m American, and I already know how to handle burgers,” he said, as a salsa tune played in his restaurant. “The Cambodians, they eat the bun and then a little bit here and a little bit there. I say, ‘No, you just press down on the bun and eat it.’ And sometimes they say, ‘Don’t tell me how to eat. I’ll eat it my way.”’

Mike’s experience pitching hamburgers in Phnom Penh offers a look at the particular kind of culture shock experienced by people returning to their own culture.