A quick pickle of red onion serves as a tangy counterpoint to meaty swordfish in this simple slider recipe. And charring sweet, ripe summer cherry tomatoes (I used Sun Gold cherry tomatoes, but feel free to use whatever looks best) gives them an interesting background smokiness that complements their natural sweetness nicely. Together, it's a harmony of flavors and textures, and these lightened up sliders are an appetizer you won't soon forget.
Preheat a gas grill or cast-iron grill pan on medium heat.
Meanwhile, dissolve the salt and honey in the vinegar and add the onion. Heat half of the grapeseed oil in a small sauté pan and add the cherry tomatoes. Cook, undisturbed, until most of the tomatoes burst and are charred, about 10 minutes. Then, pop any tomatoes that haven't burst and give it a stir.
Rub the swordfish with the remaining grapeseed oil and season with salt and pepper, to taste. Grill the swordfish until grill marks appear on both sides, about 3-4 minutes per side. Once the tomatoes have cooled slightly, drizzle with extra-virgin olive oil, to taste.
Cut the swordfish into slider-sized portions (you may want to cut parallel to the work surface as well to make them thinner). Place in the buns, topped with some pickled onions and the charred cherry tomatoes.