Preheat a medium saucepan over medium heat. When warm, add oil, onion, tomato paste, smashed garlic, smoked paprika, Calabrian chilies, salt and pepper. Saute for 30-60 seconds or until fragrant. Add bay leaf, red lentils, and water. Bring to a boil, lower to a simmer and cook, partially covered until lentils are broken down and loose, about 15-20 minutes. Remove and discard onion, garlic and bay leaf. Give it a good stir and taste for seasoning.
In the meantime, preheat the oven to 400 F degrees. Arrange the salmon filets (skin-side down) on a parchment-lined baking sheet. Season the fish with salt and pepper. Mix mayo and mustard in a small bowl and spread on the flesh side of the fish. Combine the sugar, paprika, garlic powder, and cayenne in another small bowl and sprinkle over the fish. Bake at 400 F for 10 minutes for 1-inch thick fish filets. Cook for less time if the fish is thinner. If the fish is very thin (like some sockeye salmon), I prefer to broil them instead for 3 minutes and let them rest for 5 minutes.
Serve the salmon filets over the saucy lentils. Serve with a squeeze of lemon and fresh herbs, if desired.
*Or keep fish simple: drizzle with olive oil, season with your favorite spice blend and roast at 400 F for 8-10 minutes.