Preheat the oven to 375°F (190°C).
In a small saucepan, combine pineapple juice, honey, soy sauce, olive oil, grated ginger, garlic, and red pepper flakes (if using). Bring to a simmer over medium heat. Let the sauce cook for 5-7 minutes until it thickens slightly. Remove from heat.
Season the salmon fillets with salt and pepper on both sides.
Place the salmon fillets on a baking sheet lined with parchment paper or lightly greased.
Brush each fillet generously with the honey-pineapple glaze, reserving a bit for serving.
Bake the salmon for 12-15 minutes, or until the fish flakes easily with a fork and is cooked through.
Once cooked, drizzle the remaining glaze over the salmon fillets.
Garnish with fresh cilantro and sesame seeds before serving.