A new plan to change the way students are admitted to New York’s elite public high schools is infuriating members of some Asian communities who feel they will be pushed aside in the drive to admit more than a handful of black and Latino students. But in a series of forceful statements on Tuesday, Richard A. Carranza, the schools chancellor, offered a blunt rebuttal to their claims. “I just don’t buy into the narrative that any one ethnic group owns admission to these schools,” he said on Fox 5 New York.