Pesto Salmon

Bahan-bahan (4 porsi)

• 4 (6-ounce) salmon fillets (skin on)
• 3/4 teaspoon kosher salt (divided, plus additional for serving)
• 1/2 teaspoon ground black pepper (divided)
• 6 tablespoons prepared basil pesto (divided)
• 2 pints cherry or grape tomatoes (left whole)
• 1 small red onion (thinly sliced)
• Squeeze of fresh lemon juice (for serving)
• Chopped fresh basil (optional for serving)