Place the ribs in a large baking dish, salt both sides, and place in the oven. While the ribs are cooking, place the chopped onions, celery, carrots, garlic, salt and olive oil in a pot over medium-high heat. Cook until the onions become translucent, about 10 minutes. Add the wine and ketchup and reduce for 20 minutes. Remove the ribs from the oven and lower the temperature to 300 degrees F. Pour the vegetable mixture over the ribs and return them to the oven for 3 1/2 hours.
While the ribs are cooking, prepare the corn salsa. Preheat a grill or grill pan over medium-high heat. Place the corn on the grill and grill about 10 minutes, until lightly charred and cooked. Cut the kernels off the cobs. Toss the corn, zucchini, red onion, lime juice, olive oil, cilantro, salt, and pepper together. Allow the salsa to marinate for at least 2 hours.
Remove the short ribs from the oven, and allow the meat to rest for 30 minutes. Shred the beef and assemble in the corn tortilla with the corn salsa and a dollop of crema. Garnish with cilantro.
*Note: Crema is the Mexican version of creme fraiche - it is more similar to extra thick cream than sour cream, but sour cream would be a suitable substitute.