Microwave limes in a small bowl to release essential oils. Since these will be hot coming from the microwave, set them aside until just cool enough to handle. Season fish with salt and pepper and place in a non-reactive container for marinating. Squeeze lime juice over fish and add rinds to the bowl. Pour tequila over fillets, cover and let marinate in refrigerator for at least 2 hours.
About 20 to 25 minutes before mealtime, prepare orange beurre blanc by combining orange juice and wine in a saucepan and simmering on medium heat until reduced by half the volume. Stir in heavy cream, bring to a gentle simmer, and allow to reduce and thicken over low heat. Stir in parsley and set aside briefly in a warm place.
Heat oil over medium heat in a large saute pan and add butter. Sear marinated fillets flesh side first, leaving undisturbed for at least 2 to 3 minutes to allow the surface to begin to caramelize and prevent tearing of the fish. Flip over to sear the skin side. Allow to cook for 5 to 8 minutes or until flesh springs back when gently prodded. Remove to a tray and let rest.
Whisk butter into sauce just before serving and spoon over and around the fish.