In a small saucepan, over medium heat, add 1 cup of water and 1/2 cup rinsed lentils. Bring to a boil, then reduce the heat to a simmer and cook for 15 minutes. Drain and set aside.
Season the salmon steaks with salt and pepper on all sides. In a large nonstick saute pan, over medium high heat, add 1 tablespoon of the olive oil. When the oil is hot and shimmering add the salmon fillets. Cook for 3 minutes, then turn and cook for 1 to 2 minutes on the other side. Remove the fillets to a baking sheet fitted with a rack and put in the oven.
Add the remaining 1 tablespoon of olive oil to the same pan, over high heat. When the oil is hot add the onions, capers, olives and anchovies. Stir often until the onions are just starting to caramelize. Add the garlic and red pepper flakes and saute for 2 minutes more. Stir in the tomatoes, red wine vinegar and the lemon juice. Reduce the heat to a simmer and cook for 3 to 4 minutes. Add the lentils and adjust the seasoning, if necessary. Stir in the basil and parsley and remove from heat.
Remove the salmon from oven, and transfer the fillets to serving plates. Top each serving with the puttanesca and garnish with a whole basil sprig.