Dyens studied guitar with the Spanish classical guitarist Alberto Ponce and analysis with Désiré Dondeyne. He has won several prizes in competitions for classical guitar performance as well as for composition.
As a performer, Dyens is known for his extraordinary capacity for improvisation. Essentially unique among classical guitarists, Dyens frequently opens his concerts with an improvised piece, in order to help him get a feel for the hall and the audience. His guitar music draws on many elements of folk music and jazz, and has become popular with players. Tango en Skaï (1985), is one of his best-known pieces, but also widely played is the more extended Libra Sonatine (1986) written in three movements: "India", "Largo", "Fuoco", composed after Dyens had suffered a heart attack. Skaï is a French slang term for imitation leather, and here references the Gauchos of Argentina and Southern Brazil who are known for their distinctive leather outfits. Hence "Tango en Skaï" is a humorous, gaudy take on the tango. In addition to being the most prolific guitar composer of his generation, Dyens has also released several volumes of arrangements. Ranging from Jazz standards to Brazilian folk music, these arrangements have made their way into the repertoire of both professional and amateur guitarists. Dyens tours extensively and has performed at many music festivals and held master classes at many locations across Europe, the United States and Asia.