Combine paprika and oregano. Put mushrooms, capsicum and onion into a large bowl. Sprinkle over paprika mixture, season. Drizzle over the oil, toss to coat. Use a 7cm scone cutter to cut 3 circles from each tortilla.
Preheat barbecue plate or grill on high until hot. Reduce heat to medium-high. Barbecue tortilla rounds, in batches, for 1-2 minutes each side until light golden. Remove to a wire rack to cool.
Add the mushroom mixture to the barbecue plate, cook, turning often 6-8 minutes until tender. Return to the bowl.
Dollop avocado onto each tortilla. Top with mushroom mixture and coriander. Serve with lime.