Season Halibut with lime zest, salt, pepper and paprika. Set aside to marinate for 15 minutes.
In your food processor, process your garlic, ginger, onion and lime juice until smooth or finely minced. This could pose a challenge for large processors, since its a small amount of ingredients. If so, do it by hand then add in the lime juice.
Melt butter in a non-stick skillet or frying pan. Over med-high heat, pan sear the halibut, about 2-3 minutes per side until cooked through. (Cook time will vary based on the thickness of your fish).
Carefully place fish on a baking sheet or plate tented with foil.
In the same pan, add your mixture from the food processor and saute for 4 minutes. If you need to add a smidge more butter, do so.
Add in your Thai red curry paste and tomato paste, blend well and saute for 3 minutes.
Add in the wine and stir briskly, once its simmering add in the coconut milk, sugar and some salt & pepper.
Stir, taste and adjust seasoning or heat if necessary. If you would like it spicier, add in a pinch or two of Cayenne pepper.
Simmer for 10 minutes.
Remove from heat.
Place the fish gently into the pan of sauce, allow it to sit for a minute or two and serve.
OR plate the fish and spoon the sauce around it.