In this corner, weighing 154 pounds, hailing from Mexico City and wearing the red-and-silver mask . . .

Performance artist Guillermo Gomez-Pena strips off the spangled shroud. Looking like something Liberace's tailor sewed for Spiderman, the mask is actually a copy of the design donned by a popular Mexican professional wrestler named Doctor Nuclear.

When Gomez-Pena slips the mask on and takes to the stage, he grapples with something slippery, always changing: border culture.

``I'm developing this character called The Warrior for Gringostroika,'' Gomez-Pena says. ``He's a kind of social wrestler of the '90s. He fights for perestroika in the U.S.''

The Warrior for Gringostroika appears in Gomez-Pena's new one-man performance piece, ``Indocumentado #1432900.'' It premiers tonight and plays again at 8 p.m. tomorrow at On the Boards, 153 14th Ave. (325-7901).

``In many ways you can say the main character of this piece is an undocumented Christopher Columbus,'' Gomez-Pena says between bites of a hasty takeout lunch of tacos, rice and beans. ``He comes across the border illegally and looks at the U.S. with new eyes.''

Border culture. This is the obsession of Gomez-Pena, whom the Los Angeles Times counted among ``the faces to watch in the performing arts in the 1990s.''

He ``gives voice to the new demographics of North America at the same time he envisions a borderless Utopian future,'' said the

Times.

Border culture. Gomez-Pena explains the term in a 1 1/2-page document. But he always has something new to say on the subject.

``Two days after the fall of the Berlin Wall, the California National Guard was relocated to the U.S.-Mexican border,'' he says, maneuvering a handful of tortilla. ``The South has replaced the East as the ultimate other. There's a new gallery of enemies that are citizens of the Evil Empire. Colombian drug dealers, Mexican migrant workers and radical artists.''

The 34-year-old artist maintains studios in San Diego and Tijuana. His home? He says he lives in the region that extends from Mexico City to San Francisco.

He smiles. ``It's a conceptual house, no?''

Born in Mexico City, Gomez-Pena studied linguistics at the university there. Then he majored in ``post-studio'' art at California Institute of the Arts outside Los Angeles.

An earlier Gomez-Pena piece, ``Border Brujo,'' toured 60 cities around the world. Last year it won a New York Dance and Performance Award and the Prix del la Parole at the International Theater Festival of the Americas in Montreal.

On the Boards teamed with 911 Arts/Media Center to present ``Indocumentado,'' part of 911's Goodwill Arts Festival program titled ``Origins: the Experience of Multi-Culturalism.''

``He's one of the most representative artists we could possibly invite,'' says 911 executive director Robin Reidy.

``In a way he's trying to do the same thing as Ted Turner - establish some kind of understanding and tolerance to make everybody equal, rather than have dominance of one culture over another.''

Along with art, Gomez-Pena also practices journalism, reporting on Mexico-American relations for the radio program ``Crossroads,'' and writing for the Mexico City daily newspaper, La Jornada.

``What I can say as a journalist I don't perform. And vice-versa. My voice as a performance artist can be as frantic, fractured and strident as I want it to be. There are no limits.''

On stage, he shifts from wrestler to punk mariachi to disc jockey to a skeleton that speaks in tongues.

Many tongues. English, Spanish, Spanglish, Inglenol. Even a made-up Aztec-like dialect spiced with French and Asian influences that Gomez-Pena calls ``my personal Esperanto.''

``I tend to use 90 percent English in an area without a strong Spanish-speaking community,'' he says. ``I still want to use that 10 percent to have people get used to the fact that . . . this cultural other is no longer over the border. It's in their own neighborhoods.''