I think a moderate carb plan like south beach is a better approach for a vegan than say Atkins.
(I'm pescatarian).

But here are a few ideas (check the sodium on any products, as I don't pay much attention to sodium)- your carbs will be higher than a meat eater, but I still think you can use the basic principles of the plans to improve your diet.

The basic principles I refer to: eat whole, unprocessed foods; cut out the whites and the starches; eat mainly veggies, protein, healthy fats, and some low glycemic fruits.

Breakfasts:
1. tofu scramble with nutritional yeast, spinach, mushrooms, etc...
2. tvp oatmeal http://lowcarbdiets.about.com/od/br.../tvpoatmeal.htm
3. smoothie made with almond milk, frozen berries, flax seed or nut butter, etc...
4. beans and salsa (common in central america)
5. make a cereal of nuts, coconut, freeze dried berries, etc...serve with almond milk.

lunches:
1. salads with veggies, olives, artichoke hearts, nuts, tofu, beans, Quorn cutlets, etc...
2. make your own soups with low sodium broth- or this time of year, gazpacho
3. crudites with a variety of fun dips- baba gnouish, hummus, peanut butter, guacamole,olive tapenade, etc....

dinners:
1. vegetable/tofu stirfry
2. tofu "breaded" in almond flour and fried, served with veggies
3. portabello "pizza"- scoop gills, add tomato sauce or diced tomato and Italian spices, sprinkle nutritional yeast and pizza toppings of choice- bell peppers, onion, an olive if that won't be too much sodium, etc...

Best of luck- being low sodium, vegan and low carb is a tall order, but decreasing carbs (even if not as much as an average low carber) will be very helpful IMO.