Preheat the oven to 425°F (220°C). Lightly grease a baking dish with oil and place the salmon fillet inside. Let it sit at room temperature while preparing the sauce.
In a small food processor, combine garlic, cilantro, olive oil, lime juice, and kosher salt. Blend until smooth and well combined.
Season the salmon lightly with salt and black pepper.
Spoon the garlic cilantro sauce generously over the salmon, spreading it evenly. Reserve a little sauce for serving.
Arrange the tomato slices and lime slices over the top.
Bake the Cilantro Lime Salmon in the upper half of the oven for about 8 minutes for a 1-inch thick fillet, or until it flakes easily with a fork. The internal temperature should reach 125–130°F.
Remove from the oven, loosely cover with foil, and let rest for 5 to 8 minutes.
Serve warm with the reserved garlic cilantro sauce.