1. Whisk together first 6 ingredients in a large bowl. Add tomatoes and next 4 ingredients (through arugula); toss. Top with cheese.
Wine note: Terredora Di Paola Falanghina 2008 ($16) is a crisp and citrusy white with acidity to cut the flavorful oil in this salad. Light body and mineral nuance pair well with tuna, while a slightly peppery finish matches the herbaceous arugula. -Jeffery Lindenmuth