Using on/off turns, mince garlic and ginger in processor. Add beans, reserved bean liquid, cashew butter, rice vinegar, soy sauce, chili-garlic sauce, and ground star anise. Process mixture to coarse puree. Add cilantro and green onion; process to combine. Transfer to bowl; garnish with whole star anise, if desired.
*Available in the Asian foods section of many supermarkets and at Asian markets.