Making tzaziki is easy. This is a basic recipe that works well enough with all kinds of substitutions, depending on dietary restrictions.
It is possible to use sunflower seeds and tofu to replace the hemp seeds. In this recipe, I used half hemp and half soy, because hemp, while being nutritious, is not cheap. Using just shelled hemp seeds is very possible.
If using sunflower seeds, you should pre-soak them for 1-2h prior to blending. If using only tofu, you may not require extra water in the recipe.