How to Make It
Preheat the oven to 350°. In a food processor, puree the whole grapes. Pass the puree through a coarse sieve into a large bowl. Add the quartered grapes, scallions, garlic, chiles and Sriracha to the bowl and toss.
In a large nonstick skillet, heat 1 tablespoon of oil until shimmering. Season half of the fillets with salt and pepper and add them to the skillet, skinned side up. Cook over high heat until the fillets are golden brown on the bottom, about 3 minutes. Transfer the fillets to a rimmed baking sheet. Repeat with the remaining oil and fillets. Transfer the fish to the oven and cook until just white throughout.
Add the cilantro and vinegar to the grape salsa and season with salt. Transfer the fish to plates; spoon the salsa on top and serve.