Combine tomato, fennel, onion, dill, vinegar and 1/4 teaspoon salt in a medium bowl.

Cut salmon into 4 equal portions, sprinkle with the remaining 1/4 teaspoon salt and pepper. Heat oil in a large nonstick pan over high heat until shimmering but not smoking. Cook the salmon, skinned-side up, until golden brown, 3 to 5 minutes. Turn the salmon over and remove the pan from the heat. Allow the salmon to finish cooking off the heat until just cooked through, 3 to 5 minutes more. Serve immediately with the salsa.

Tip: To skin a salmon fillet: Place it on a clean cutting board, skin-side down. Starting at the tail end, slip the blade of a long, sharp knife between the fish flesh and the skin, holding the skin down firmly with your other hand. Gently push the blade along at a 30 degree angle, separating the fillet from the skin without cutting through either. Or have your fishmonger do it for you.