Using a sharp knife, remove kernels from the corn cob. Freeze freshly shucked kernels overnight.
Place fresh corn into a heavy skillet over medium-high heat. Cover and cook, without stirring, until a char develops on the corn, about 10 minutes. Remove from heat.
Meanwhile, toss Romaine, chicken, cherry tomatoes, red onion, green onion, cilantro, jalapeño, cotija cheese, and avocado together in a bowl. Toss in charred corn.
For dressing, whisk crema con sal, mayonnaise, lime juice, and Tajin together in a small bowl. Drizzle over salad.
