Rinse lentils well in cold water. Place lentils in saucepan, cover with water (1 to 2 cups, or 250 to 500 mL) and simmer, covered, until lentils are tender, approximately 30 minutes. If needed, add more water. Drain lentils and set aside.
Meanwhile, in large skillet, heat olive oil over medium heat. Sauté onion and garlic until softened. In a small bowl, combine curry paste, curry powder, turmeric, cumin, chili powder, salt and pepper. Add curry mixture to onion and continue cooking over high heat for 1 to 2 minutes. Add the tomato purée and reduce heat.
Stir in tofu or baby shrimp and lentils, and simmer for about 5 minutes.
When lentils are heated through, divide between four dishes and serve.