Heat oven to 400 degrees.On large, rimmed baking sheet, toss tomatoes with 1 tbsp of oil and 1/4 tsp of salt and pepeer.
In a small bowl, combine the onions,parsley, dill, lemon zest and the remaining tbsp of oil.
Place the salmon, skin down, in the center of the pan, pushing the tomatoes to the sides. Season the salmon with 1/4 tsp of pepper and drizzle with the lemon juice. Top with the herb mixture and roast until the salmon is opaque throughout, about 20 min.