Prepare white beans as per packet directions. Drain.
Meanwhile make chimichurri combining all ingredients in a food processor. Process until smooth. Season to taste.
Brush corn with some of the olive oil. Cook corn on a heated grill plate over medium heat, turning occasionally for 15 minutes or until charred. Cool. Cut kernals from cobs.
Place beans and corn on a serving platter with the onion, tomatoes, avocado, cucumber, coriander, juice and olive oil. Serve with chimicurri.