I don't know if they are technically allowed (don't have a package to check the ingredients), but the Hebrew National 97% fat free hot dogs are really tasty, and about 45 calories. I don't eat them often, but every now and then I get a hot dog craving, and will have one, or take some along if I'm going to a cookout. You will be getting a lot of sodium with them and sauerkraut though, so don't be alarmed if you retain some water after eating them (as Ruth said).
Life's a journey, not a destination.
It's easier to stay on plan than to get back on plan.