Pat vegan fish fillets dry.
In a bowl, mix olive oil, lime juice, garlic powder, paprika, salt, and pepper.
Brush marinade over fillets; let rest 8–10 minutes.
Preheat grill to medium-high; oil grates lightly.
Grill fillets 6–7 minutes per side until golden and smoky.
In another bowl, combine pineapple, bell pepper, onion, jalapeño, lime juice, cilantro, and salt to make relish.
Top grilled fish with pineapple relish before serving.