Cook the rice following the absorption method on the packet. Rinse under cold water to refresh. Drain well. Spread the rice onto a baking tray, cover and refrigerate 1 hour if time permits.
Whisk the oil, vinegar, paprika and salt and pepper in a ceramic bowl until well combined. Add mushrooms and stir to coat. Cover and stand 30 minutes to allow mushrooms to absorb the dressing. Place onions onto a microwave-safe plate, cover loosely with damp paper towel and microwave on High/100% for 3 minutes until just tender.
Preheat barbecue plate on medium. Add the chorizo and cook 2-3 minutes until it starts to colour. Add the onions and cook for 3 minutes, then add the marinated mushrooms, cook, tossing for 3-4 minutes until mushrooms are tender.
Spoon the mushroom chorizo mixture into a large bowl, add the rice, almonds, olives and parsley. Toss gently to combine. Serve with barbecue fish, chicken or lamb.