Grilled Mediterranean Sardines, Chickpeas, Calabrian Chile, and Pickled Red Onion
For the Pickled Red Onion:
Thinly slice red onion lengthwise. In a saucepan, combine remaining ingredients and simmer 10 minutes; let cool. Pour pickling liquid over onions, cover, and refrigerate for at least 1 day.
For the Chickpeas:
In a saucepan, combine chickpeas, fennel, onion, garlic, and bay and add enough salted water to cover. Simmer until chickpeas are tender. Let cool in cooking liquid; drain, reserving liquid. Toss ¾ cup chickpeas with oil, tomato vinegar, and smoked paprika; reserve. Transfer drained chickpea mixture to blender and purèe until smooth and thick. Adjust consistency with cooking liquid, if necessary. Season with salt and white pepper.
To Assemble and Serve:
Prepare and heat grill. Season sardine fillets with salt and white pepper. Grill fillets briefly skin-side down until lightly marked. Spread a large spoonful of chickpea purèe on a serving plate. Top with 3 fillets. Toss whole chickpeas with roasted pepper, Calabrian chile, and pickled onion; spread over fillets. Drizzle with oil. Zest lemon over the dish. Finish with celery leaves, parsley, and sea salt.