Two of the most impish and irreverent makers of underground movies in the 1960s were brothers George and Mike Kuchar. Their mocking style of Hollywood movies was seltzer to the very self-important, flatly serious mix of avant-garde movies of the time. They went separate ways, but a tinge of the style from "Hold Me While I'm Naked" hung on. George Kuchar settled in San Francisco. With these filmmakers technology was always a spur, a creative stimulus. Several years ago Kuchar acquired an 8mm video camera which allows him to record, edit in the camera, reshoot, edit, etc., with the undreamed of freedom of a diarist. Monday he comes to Hallwalls, 700 Main St., to show his recent work at 8 p.m. Included will be a 1988 film, "Summer of No Return," made in collaboration with students, and another will be a portion of his video diaries, "The Thursday People."