Trim fat from lamb. Partially freeze lamb. Thinly slice across grain into bite-size strips. Set aside.
For sauce, in a small bowl combine 1 tablespoon oil, lemon juice or vinegar, rosemary, oregano, and pepper. Set aside.
Pour 1 tablespoon cooking oil into a wok or large skillet. (Add more oil as necessary during cooking.) Preheat over medium-high heat. Stir-fry garlic in hot oil for 15 seconds. Add carrot and onion; stir-fry for 3 to 4 minutes or until crisp-tender. Remove vegetables from wok.
Add lamb to the hot wok. Stir-fry for 2 to 3 minutes or to desired doneness. Return cooked carrot and onion to the wok. Add sauce, spinach, and tomato wedges. Stir all ingredients together to coat with sauce. Remove from heat. Serve immediately over hot cooked rice, if desired. Top with crumbled feta cheese. Makes 3 servings.