Whisk together the juice, 1/4 cup vinegar, 1/4 cup olive oil, honey, and salt and pepper to taste. Add the onions and jalapeno, toss to coat and let sit at room temperature while you grill the fish.
Heat a grill (gas or charcoal) to medium-high heat. Brush the fish on one side with canola oil and sprinkle with salt, pepper, the paprika and 2 teaspoons cumin. Flip, brush the second side with canola oil and sprinkle with salt and pepper. Place the spice-rubbed side down on the grill, cover and cook until the first side is crusty and golden-brown, 5 to 6 minutes. Flip and cook uncovered another 5 or so minutes, until just barely cooked through. Place the fish on a platter and top with the onion mixture. Let the fish sit at room temperature for 30 minutes to 1 hour.
While the fish cures, make the avocado and mango topping. Put the avocado and mango in a large bowl. Add the remaining 2 tablespoons olive oil, the remaining1 tablespoon red wine vinegar, the remaining 1/2 teaspoon cumin, the cilantro, and salt and pepper and toss gently to combine. Scrape most of the onion mixture off the fish, spoon the mango mixture across the top, garnish with whole cilantro leaves and serve.