Arugula salad is best prepared fresh, as it can wilt quickly. However, you can prepare the salad ingredients up to 1 day in advance. Store the baby arugula in an airtight container and keep the lemon juice, extra virgin olive oil, and black pepper separate until you're ready to serve. Mix the dressing into the arugula just before serving to maintain the peppery arugula texture and freshness. Serve the steak over the bed of arugula.