Put tofu in food processor and whirl until smooth. Use firm for a stiffer dip, soft for something more drippy. Add in the rest of the ingredients and whirl to blend. To make dressing, whirl in a little soy milk, how much depends on how thick you like your dressing, personally I don't like it gloppy so I use soft tofu and enough soy milk to make it a little runny.
Without diluting it with soy milk, it comes out to about 8 calories/tablespoon, way lower than any commercial stuff. If you want it tangier, add a little more lemon juice, do not use vinegar as a substitute, I tried a couple of recipes using vinegar before I decided to work on my own, and I think it tastes well...vinegary.