In a small saucepan, combine pineapple juice, soy sauce, brown sugar, minced garlic, grated ginger, lemon juice, and red pepper flakes. Heat over medium heat and whisk occasionally until the glaze thickens slightly, about 5 minutes.

While the glaze cools, pat the salmon fillets dry with paper towels. Brush both sides with olive oil and season with black pepper and salt.

Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper. Place salmon fillets skin-side down, spoon half the glaze on top, and bake for 12-15 minutes.

Once cooked through, drizzle remaining glaze over each fillet and serve warm.