Heat a large skillet over high heat until very hot. Add oil and corn in a single layer. Cook undisturbed for 2 minutes until charred on the bottom. Toss and cook 1 to 2 minutes more until golden and caramelized all over. Season with salt, spread on a plate, and cool.
Whisk together lime juice, lime zest, olive oil, honey, cumin, salt, pepper, and chili powder in a small bowl until emulsified. Taste and adjust.
Dice avocados into ¾-inch chunks.
In a large bowl, combine cooled corn, cherry tomatoes, red onion, and jalapeño. Pour three-quarters of the dressing over and toss gently to coat.
Add avocado and cilantro. Fold very gently to keep avocado chunks intact.
Taste and drizzle over remaining dressing as needed. Adjust salt and lime. Serve immediately or rest up to 20 minutes before serving.