Mushroom Salad

From lemon(s), grate 1/2 teaspoon peel and squeeze 1/2 cup juice. In 4-quart saucepan, heat lemon peel and juice, 3 tablespoons oil, garlic, 1/2 teaspoon salt, and 1/4 teaspoon freshly ground black pepper to boiling on high. Reduce heat to medium and simmer 30 seconds. Stir in mushrooms, parsley, and chives. Transfer to large self-sealing plastic bag. Seal bag, pressing out excess air. Place bag in bowl and refrigerate 6 hours or overnight. Place sieve over large bowl; drain mushrooms over bowl (do not discard drained marinade). Discard garlic cloves; set mushrooms aside. Add remaining 1 tablespoon oil to marinade in bowl; whisk until blended. Add arugula and mixed greens; toss to combine. Serve mushrooms on greens. Garnish with additional snipped chives and Romano shavings.