Combine lemon rind and next 4 ingredients in bottom of a large shallow dish; add fish fillets, turning to coat. Cover and chill 1 hour.
Remove fish from marinade, discarding excess marinade. Grill over medium-high heat (350° to 400°) for 3 minutes; turn carefully, and grill for 2 minutes. Sprinkle fillets with salt before serving. Garnish, if desired.