A good place to start with the Finch and arrays is to introduce students to the Finch API methods that return data in array format: getAccelerations, getLightSensors, getObstacleSensors. These methods were created to minimize the number of calls required to receive sensor data.
The Finch as Data Collector
Arrays of real world data can be easily created by having the Finch record its sensor data in an array over time. This data can be used to create behavior after the data is recorded. For example, one can record accelerometer data, and then scale it and play it back through the LED, buzzer, or motors.