1. Preheat oven to 375°.
2. Cook orzo according to package directions; drain. Keep warm.
3. Combine breadcrumbs and next 6 ingredients (through garlic) in a medium bowl; stir in 1 1/2 tablespoons parsley. Add egg whites, stirring mixture until just combined. Shape mixture into 12 (1-inch) meatballs; cover and chill meatballs 5 minutes.
4. Heat oil in a large ovenproof skillet over medium-high heat. Add meatballs to pan; cook 8 minutes, turning to brown on all sides. Drain well; wipe pan clean with paper towels. Return meatballs to pan. Spoon marinara sauce over meatballs; sprinkle with cheese. Bake at 375° for 11 minutes or until meatballs are done. Sprinkle with remaining 1 1/2 teaspoons parsley. Serve over orzo.