Foreign-language movies dominate this week's openings. The class of the field appears to be "The Best Way," a strong first feature by Claude Miller, Francois Truffaut's former assistant director.

Previewed last winter at the American Film Institute, the movie begins a commercial engagement today at the Dupont Circle. The screenplay, an original by Miller and Luc Beraud, deals with the personality conflict between two youthful counselors at a boys summer camp. (Review, Page D2.)

"Faustine and the Beautiful Summer," Nina Companeez's 5-year-old pastoral romance about a dreamy teen-age girl's summer vacation in the countryside, also opens today at the Outer Circle 2. Isabelle Adjani, at the age of 16, may be seen among the members of the supporting cast.

Today's other arrivals are "La Grande Bourgeoise," a turn-the -century love story costarring Catherine Deneuve and Giancarlo Giannini and directed by Mauro Bolognini, at the KB Janus; "The Beast," an erotic something-or-other from Polish-French surrealist Walerian Borowcyzk at the Key; and a British documentary feature, "The Queen's Silver Jubilee," at the K-B MacArthur.

The KB management has announced an opening date of Friday, June 17, at units of the Cerberus and Janus for "In the Resim of the Senses," the controversial erotic drama from Japan's Nagisa Oshima about an extended, fatal sexual rendezvous between a gangster and his moll. The film, which had it's premiere at the 1976 Cannes Festival, was held briefly by U.S. Customs before being cleared for domestic release.

The summer repertory program at the Circle's includes a six-day engagement of the Brian De Palma doublebill, "Greetings" and "Hi, Mom!," recently shown at the AFI Theater. Scheduled for June 22-27, these insolent topical satires have acquired a fascinating patina. They now seem to be invaluable as well as funny period pieces, instantly recalling the pop culture climate of 1968 and 1970, respectively.

In addition, they also reveal how distinctive De Palma's style and sense of humor were from the beginning of his career and document the early star potential of a young actor named Robert De Niro, whose latest movie, "New York, New York," will be opening on Wednesday, June 29.

The Smithsonian Institution will present a free six-day festival of films and slide shows on family and community themes in conjunction with the upcoming symposium, "Kin and Communities: The People of America." The film showings begin Sunday, June 12, and the symposium two days later.

The selections include the recent Academy Award-winning documentaries, "Harlan County, U.S.A." and "Number Our Days" plus "Six American Families," "Margaret Mead's New Guines Journal" and "Grey Gardens." For detailed information about screening sites and starting times, call at Smithsonian information desk at 381-6264.

The Corcoran School of Art will offer two courses inBeginning Film making this summer.A morning course meets from 9 a.m. to noon on Monday through Thursday starting June 13 and ending July 21. The evening course meets on the same days for the same period from 6 to 9 p.m. The instructor will be area filmmaker-teacher Michael Day, who plans to supplement of films by Chaplin, Truffaut, Welles, the Hubleys, Bruce Baillie, Jordan Belson and many others. For further information, call 628-9484.

Local producer-academician Sheldon Tromberg is offering five-week seminar sessions in the theory and practice of screenwriting. The first of three projected sessions begins Wednesday, June 8. For detailed information, call 966-7799 or 244-3770.