Preheat the oven to 400 degrees Fahrenheit. Line a rimmed baking sheet with parchment paper.
Dry the fish well with a paper towel. Lightly brush the inside and out of the fish with olive oil.
In a large mixing bowl, stir the salt and water together. The salt should feel like wet sand. If more is needed, add slowly, mixing after each addition until the right texture is achieved.
Scoop half of the salt onto the baking sheet and pat into an even layer to create a bed.
Gently place the lemons and herbs into the cavity of each fish. Place fish on top of the salt bed and pat the rest of the salt around the fish so it is fully encased in the salt mixture.
Bake for 25–30 minutes. Remove from the oven and allow to rest for 5–10 minutes.
Using a large spoon, knife, or spatula, crack open the crust and remove. Use a dry brush to remove any excess salt.
Gently peel the skin off the fish and discard, and carefully remove the first filet from the bones, placing on a platter.
Remove the bones and herb stuffing and then gently scoop bottom filets out of the bed of salt, being careful not to puncture the skin underneath. Set these on the platter with the others.
Garnish with more torn fresh herbs, a drizzle of olive oil, and a bit of flaky sea salt to taste.
Serve with the roasted tomato clusters and lemon halves.
