Arugula Microgreens are just the baby versions of actual arugula.  They're best grown indoors.  Seed heavily and water thoroughly.  Cover the plants for the first few days to allow them to stretch.  This makes them reach for light and grow tall, making it very easy to harvest when they're ready.  They're excellent in salads, sandwiches or soups.  They're spicier than the full grown version.