Alessandra Corona, former principal dancer with Ballet Hispanico, presents her Alessandra Corona Performing Works in two world premieres by Kristian Cellini of Rome, and Guido Tuveri who, like Ms. Corona, is a native of Cagliari, Sardinia.   Cellini's ballet, "Amore Impossibile," is inspired by The Lady of the Camellias, and set to music by Chopin with original music by American composer Thomas Lentakis.   Tuveri created "Just Joy" to show how, even in difficult times, dance can always bring passion and joy.   "Just Joy" is set to songs from Sardinia, sung in the native language, along with additional music by Lentakis.