Transfer nuts to paper towels to drain and cool. Mince garlic and chop parsley.
Quarter tomatoes and coarsely crumble feta.
In a large bowl whisk together garlic, parsley, vinegar, remaining tablespoon oil, and salt and pepper to taste. Add tomatoes and feta and gently toss to combine. In a large sieve drain orzo and rinse slightly until just warm. Drain orzo well and add to tomato mixture, tossing until just combined. Serve topped with nuts.