Take frozen peas out of the freezer and let thaw while preparing the cauliflower.
Combine oil and spices (curry powder through ground pepper) and toss with cauliflower and red onion until all pieces are well-coated. Place cauliflower in a baking dish and roast for 25 to 30 minutes, stirring about every 15 minutes for even cooking. The cauliflower should be crisp-tender and golden brown when done.
Place in a serving bowl, then stir in peas and cilantro. Let cool a bit and serve.