Roughly grind the coriander seeds to a coarse consistency in a mortar and pestle. Set aside.
Heat BBQ to MED-HI. Place the corn cobs, husk on, on the barbecue and cook for approximately 30 minutes, turning a few times until the husks are mostly charred all the way through.
Add chorizo after about 20 minutes and barbecue until crisp. Set aside.
Place limes, face down on the grill, in the last 5 minutes of cooking and chargrill briefly. Set aside.
Remove corn from the heat and remove the husks. Use a knife to remove the kernels from the cob and place in a bowl with the chorizo.
Briefly dry roast spices in a cast iron pan on the barbecue until fragrant.
Add spices, salt, juice of the limes and oil to a small bowl and whisk together.
Toss the dressing with the corn. Carefully add the avocado. Season with a pinch of salt and finish with plenty of fresh coriander.
