Base this salad on your favorite produce available at a local market for ultimate freshness.
Heat a grill or grill pan. Wash greens, and let excess water drain off. Place in a plastic bag lined with paper towels until ready to use.
Cut vegetables into sizes that are manageable for the grill. For example, slice yellow squash and eggplant in half lengthwise, leaving small zucchini whole; cut bell peppers into quarters, and discard ribs and seeds; cut corn cobs in half crosswise; slice radicchio into wedges; and leave bunches of cherry tomatoes attached to the vine. Brush vegetables with olive oil, and grill until cooked through, turning as needed.
While vegetables are cooking, transfer greens to a large serving dish. Vegetables will cook at different times, so as they are done, remove them from the grill and cut into smaller pieces. Add them to the bowl of greens, tossing well. The heat of the grilled vegetables will wilt the greens slightly. Season with salt and pepper, and serve.