This is one of my favorite simple snacks. It's about 3 calories, and surprisingly filling. Best of all, you can eat as much as much as you want until you're full, and it's all good for you. (I love that!) All you have to do is peel and chop up cucumber as well as red onion super thinly. Add a dash of salt and pepper and finish with a little balsamic vinegar. Light and crisp. Yum.