In a large pot of boiling salted water, cook the corn for 3 minutes until the starchiness is just gone. Drain and immerse the corn in ice water to stop the cooking and to set the color. When the corn is cool, cut the kernels off the cob, cutting close to the cob, and place them in a large bowl.
Toss the avocados with the lemon juice and add them to the bowl with the corn. Add the tomatoes, red peppers, onion, jalapeno peppers and lime zest to the bowl.
Whisk the lime juice, olive oil, 2 teaspoons kosher salt, black pepper, garlic, and cayenne pepper together in a small bowl and pour over the vegetables. Toss well. Keep refrigerated until ready to serve.