In a bowl, combine garlic, sesame oil, 1/4 cup soy sauce, sugar, green onions and white pepper. Add steak; mix to coat. Let sit while noodles are being prepared.
Bring a large pot of water to a boil. Add noodles and stir; cook for 3 minutes or until tender. Drain and rinse in cold water until noodles feel cold. Cut noodles with a pair of scissors into bite-size pieces.
Pour 2 tablespoons olive oil into a large saute pan. Add carrots; saute until crisp-tender. Transfer to a large bowl.
Add noodles to bowl along with remaining 1/4 cup soy sauce, cucumber and salt and black pepper to taste; combine.
Add remaining 1 tablespoon olive oil to saute pan; place over medium-high heat. When hot, add steak mixture. Saute over medium-high heat for 5 to 7 minutes or until cooked to desired doneness. Stir in mint, lemon grass and additional salt and pepper to taste. Let cool.
Place noodle mixture on a large decorative platter. Arrange meat on top. Serve cold or at room temperature.