Preheat oven to 425°F with a rack in the center. Toss the cauliflower florets and the chickpeas with the olive oil on a rimmed baking sheet. Sprinkle generously with salt and pepper. Roast, turning once halfway through, until the cauliflower is tender and browned in spots, about 35 minutes.
Meanwhile, combine the sour cream, mayonnaise, vinegar, and blue cheese in a small bowl. Stir all ingredients together with a fork, breaking up any large chunks of blue cheese as you go.
Mix together the melted butter and Frank's Red Hot in a small bowl. Pour over the cauliflower and chickpeas and toss to combine. Serve immediately, either on a platter with the dressing on the side or tossed with the greens and tomatoes.