I have been eating a lot of this lately and it's yummy and pretty healthy.
Chop english cucumbers in to bite size pieces
Chop about the same amount of tomatoes,
Chop finely a bunch of dill
Mix everything, sprinkle some salt (Mrs. Dash "It's a dilly" mix if you need to watch sodium), little spritz of olive oil (depends on hom much of this stuff you're making, but you really don't need much you can even skip this step). Mix everything and enjoy. You can really get full on this stuff and get away with relatively few calories. Obviously, if you eat a bucket full, it still adds up, but a good 2-3 cups is just a bit over 120 calories (depending on the use of olive oil), and by the time you had 2-3 cups you're feeling pretty full. I know it's not exactly "portable", but I've been bringing it to pot-lucks at my work and people can't get enough of it.
Hope this helps.