In a medium bowl, combine avocado, olives, pineapple, jalapeño, and orange segments. Add enough vinaigrette to generously coat everything and stir until combined.
Pat fillets dry with a paper towel and season with salt.
For poached fish: Bring a pot of water with a bit of salt to a gentle boil. Add fish and poach until opaque, about 8-10 minutes.
For poached fish: In a small saucepan, combine coconut milk, water, lime juice, and salt. Bring to a simmer and add fish. Reduce heat to low and simmer until fish is cooked through, about 8-10 minutes or until flaking halfway.
For blackened fish: In a small mixing bowl, combine blackening spices (brown sugar, dried oregano, cumin, onion powder, ancho powder, paprika, ground cumin, and kosher salt).
For blackened fish: Generously season each fish fillet with the blackened spice mixture on both sides.
For blackened fish: Heat a large skillet or cast iron skillet over medium-high heat and add oil and cook for 4-7 minutes, flipping halfway.
Plate the fish and serve with the poached or blackened fish, followed by citrus salsa.
