Whisk the paprika, sugar, cumin, salt, and cayenne together in a large bowl and set aside.

Heat the vegetable oil in a large Dutch oven over high heat until it just begins to smoke. Carefully add the chickpeas and partially cover the pot to catch oil splatters; cook, stirring occasionally, until they are deep golden brown and very crisp, about 10 to 12 minutes.

Use a slotted spoon to transfer the chickpeas to a paper towel–lined plate to drain briefly. While still hot, toss them into the bowl with the spice mixture, then use a fork to crush about half of the chickpeas into coarse crumbs.

Set an oven rack 6 inches from the broiler element and heat the broiler. Toss the onion with olive oil and salt on a foil-lined rimmed baking sheet, spread them into a single layer, and broil until the edges are charred, about 6 to 8 minutes, stirring halfway through.

Whisk the vinegar, mustard, honey, lemon zest, mayonnaise, and salt together in a small bowl. Slowly drizzle in the oil while whisking constantly until the dressing is thick and emulsified.

Add the charred onions and mesclun to the bowl with the spiced chickpeas and toss to combine. Drizzle the dressing over the salad, toss again, and serve immediately while the chickpeas are still crackling.