For the chipotle-lime dressing: In a small bowl, whisk together the sour cream, mayonnaise, lime juice, hot sauce, kosher salt, chipotle chile powder, cumin, black pepper, and 1 tablespoon of water. Set aside.
For the salad: Meanwhile, bring a large pot of water to boil over high heat and season generously with salt. Add the ears of corn and boil for 3 minutes. Remove the corn from the pot and let it cool to room temperature. Slice the kernels off the cob. (You should have about 4 cups of corn).
In a large bowl, gently toss together the corn, tomatoes, avocado, red onion, jalapeño, chopped cilantro, and queso fresco. Drizzle with the dressing and toss gently to coat. Sprinkle with more cilantro, queso fresco. and chipotle chile powder. Serve with lime wedges.
Tip: Substitute 4 cups of drained, canned corn for this recipe in place of the fresh corn on the cob.