Trim the beef removing any fat or sinew. Cut into thin slices lengthwise. Heat the oil in a medium frying pan over low-medium heat. Add the garlic and saute until softened. Put the beef and cook for a minute. Remove the pan from the heat and let cool slightly. Season with salt and pepper.
Whisk 2 tablespoon of olive oil and lemon juice together in a small bowl. Add the balsamic vinegar . Season with salt and toss to combine.
Arrange the cocumber in a serving dish, with the slices of cooked beef on top. Pour the dressing over and toss to coat.
Serve, share and enjoy.