LE SAMOURAI

At last available on video, Jean-Pierre Melville's breathtakingly spare crime saga now looks like a pivotal work for the genre: It boils previous Hollywood film noirs down to their existential essence and provides a clear attitudinal template for such later acolytes as Quentin Tarantino and John Woo (who's quoted on the cassette box as calling this ''the closest thing to a perfect movie'' he's ever seen). Delon exudes a mesmerizing stillness as lone hitman Jef Costello, chased through the Paris subway by the flics and drawn helplessly to the jazz pianist (Caty Rosier) who could turn him in but won't. It's all beautiful and grave, and there isn't an ounce of fat on it. A