Combine lentils, salt and 5 cups water in large saucepan. Cover, and bring to a boil. Reduce heat, and simmer, partially covered, 20 to 25 minutes, or until lentils are tender. Blend lentils with whisk for rustic texture, or purée in food processor for creamier feel.

Purée tomatoes and ginger in blender or food processor until smooth. Set aside.

Heat oil in large pot over medium heat. Add garlic, and cook 30 seconds, or until just golden, stirring often. Add tomato mixture, coconut milk, tamarind if desired, coriander, cumin, turmeric and jalapeño. Simmer 15 minutes, stirring occasionally.

Stir in lentils, and simmer, partially covered, 20 minutes. Season with salt and pepper. Sprinkle with cilantro, and serve.