Soak the ears of corn (in their husks) in a deep bowl filled with cold water for 1 hour, placing a plate or other heavy waterproof item on top of the corn to keep the ears submerged.
Preheat a grill to medium. Lay the corn on the grill and cook for 20 to 25 minutes, turning frequently, until the outer leaves are blackened. Grill the jalapenos for 5 to 6 minutes, turning periodically. Remove the corn and jalapenos from the grill and set aside to cool.
Once the corn is cool, remove the husks and silk and discard. Cut the kernels off of the cobs and place in a large bowl. Stem, seed and finely chop the jalapenos and add to the bowl with the corn, along with the tomatoes, red onions, garlic, cilantro, mint, lime juice, olive oil and salt. Stir well to combine.