Into a medium saucepan, add lentils to approximately 3 cups of water and simmer on low until tender, about 10 minutes. Drain and set aside.
In a small mixing bowl, combine the curry paste, curry powder, turmeric, cumin, chili powder, salt, sugar, garlic, and ginger; set aside.
Into a medium size skillet over medium high, heat the oil and cook onions until tender and slightly caramelized.
Stir in the curry mixture and tomatoes. Reduce heat to Low and allow to simmer 5-10 minutes.
Add the lentils and continue cooking another 5 minutes or so until heated through. Top with cilantro and serve hot.