If using fresh corn, bring a large pot of water to a boil. Add the corn and cook for 3-4 minutes until tender but still crisp. Immediately transfer to an ice bath to stop the cooking process. Once cooled, carefully slice the kernels off the cob using a sharp knife.
In a large bowl, combine the corn kernels, halved cherry tomatoes, diced bell pepper, cucumber, red onion, and jalapeño (if using).
In a small bowl, whisk together olive oil, lime juice, honey, minced garlic, and cumin until well emulsified. Season with salt and freshly ground black pepper to taste.
Pour the dressing over the vegetable mixture and toss gently to coat evenly. Add the chopped herbs and fold them in carefully. Cover the bowl and refrigerate for at least 30 minutes to allow the flavors to meld together.
Just before serving, fold in the crumbled feta cheese (if using) and diced avocado. Toss gently to preserve the integrity of these softer ingredients. Taste again and adjust seasoning as needed.