ADD the chimichurri sauce ingredients to a food processor and pulse until well-combined and consistent in texture. Set aside.
PREPARE the radicchio pineapple salad by adding the olive oil, balsamic vinegar, and sea salt to a mixing bowl. Add the radicchio to the bowl and toss well.
GRILL the pineapple spears on a grill or in a cast-iron skillet set to medium-high heat for 1 minute per side. Remove from the heat, dice and toss with the radicchio.
GRILL the fish on the hot grill set to medium-high heat for 1-2 minutes per side. If using a cast-iron skillet, add the ghee to the skillet and swirl it around the pan prior to adding the fish.
ARRANGE fish on top of the radicchio pineapple salad. Top fish with chimichurri sauce.
STORE any leftovers in the fridge for up to 2 days.