In a large pot (or rice cooker), combine water, sorghum and salt and bring to a boil. Lower heat and simmer until the water is absorbed and the grains are tender- adding extra water if necessary. About 50 minutes of cooking time.
In a small bowl combine the lemon juice, mustard and garlic and stir. While continuing to stir, slowly add the olive oil to make a thick dressing.
After the sorghum is cooked, allow to cool until warm, about 5 minutes, then toss with the dressing, scallions, onion and kale leaves.