Tara appears in the Buddhist pantheon as a female bodhisattva in Mahayana Buddhism, and later as a Buddha and meditational deity (yidam) in Vajrayana Buddhism.  She manifests in many different forms including Green Tara, White Tara, Red Tara, and as the 21 Taras.  

In this image Tara is opulently arrayed with crown and jewels, wears a flowing skirt, and holds a shawl over her left shoulder.  Her right hand is extended in the gesture of boundless giving or boon-granting (varada mudra), while her left hand is in the vitarka mudra, with thumb touching the index finger.   The vitarka mudra generally symbolizes teaching and discussion, evoking a feeling of silent wisdom by helping to prevent the devotee from entering argumentative states of mind.  In the original sculpture from which this image was taken, she would also have been holding the stem of a lotus flower in this hand. 

To contact Green Tara, one needs only to recite her ten-syllable mantra OM TARE TUTTARE TURE SVAHA.