Gently dry of excess moisture from the tofu by blotting with a paper towel.
Evenly cut the tofu into two sections. Place sections on top of each other and cut into fourths horizontally, and then cut into fourths vertically. You should have 32 cubes when done.
Coat the cubes in the egg white mixture.
In a saucepan, add the oil and place on medium heat. Once the pan is hot, add the cumin seeds, salt, ginger and garlic. Saute for about 2 minutes. Add the coriander powder and black bean sauce. Add the tofu and cook for another minute, stirring constantly (add some water if mixture is too dry).
Add the green beans and saute for about 3 minutes, stirring constantly.
Add the lemon juice and pepper. Reduce the heat to low and allow the sauce to thicken.
Enjoy this stir fry with some brown rice! Serves 4.