How to Make It
In a medium saucepan, cover the lentils with 4 cups of water. Bring to a simmer over moderate heat, then reduce the heat to low, cover and simmer for 15 minutes. Stir in the carrots, celery, onion, garlic and thyme sprigs, cover and cook for 15 more minutes. Stir in the kosher salt and cook until the lentils are softened but still slightly firm, 5 to 8 minutes. Let stand for 10 minutes.
In a small bowl, mix together the chopped tarragon, parsley and chives, kosher salt, sugar, orange zest and 1/2 teaspoon pepper. Spread the herb mixture evenly on both sides of the salmon and arrange the fillets in a large baking dish. Let marinate at room temperature for 3 hours.
In a nonreactive medium saucepan, combine the red wine, port, vinegar, shallots and tarragon and parsley stems. Boil over high heat until reduced to a generous 1/2 cup, about 10 minutes. Strain the mixture into a small nonreactive saucepan and bring back to a boil over moderate heat. Lower the heat and gradually whisk in the butter until the sauce is slightly thickened; do not let the sauce boil. Season with table salt and pepper and keep warm.
Heat a large, heavy, nonstick skillet. Brush the herbs from the salmon and cook the fillets in two batches over moderate heat, turning once, until nicely browned and just opaque throughout, about 4 minutes per side. Transfer to a plate and keep warm; cook the remaining salmon.
Discard the thyme sprigs from the lentils. Make a bed of the lentils on 6 plates. Set the salmon fillets on top, spoon the red wine sauce over the fish and lentils and serve.