Heat 1 Tbsp oil in a skillet over medium-high heat. When hot, add half of the diced onion. Cook, stirring occasionally.
Add 1 lb chorizo sausage, then cook breaking up with a spatula as needed.
Use tongs to flip every 10-15 seconds until the tortilla is evenly charred on both sides. Transfer to a damp paper towel, then wrap tightly around all tortillas.
Fill tortillas with chorizo, then drizzle on as much of the avocado crema as you like. Sprinkle with lots of diced onions and fresh cilantro. Serve immediately.