In a large skillet cook chorizo until crispy; drain on a paper towel-lined plate. Pour off all but 1 tbsp of fat from skillet and add sliced red onion. Cook, stirring over medium-high heat until just soft, about 5 minutes. Add corn kernels and chorizo and cook briefly to heat through. Fill 12 heated corn tortillas with corn mixture and serve with lime wedges, sour cream and chopped cilantro.