Heat oven to 375°F. In small bowl, mix butter, lemon peel and lemon juice; set aside.
In medium bowl, mix pineapple, cilantro, onion and chile; refrigerate until serving time.
Line 13x9-inch pan with foil. Place salmon, skin side down, in pan; sprinkle with salt.
Bake 8 to 10 minutes or until fish flakes easily with a fork. Immediately top salmon with butter mixture. Serve with pineapple salsa.