In a medium bowl, toss the whole bell pepper with 2 teaspoons of the oil, ½ teaspoon of the salt, and 1/4 teaspoon of the pepper. Place the whole pepper on the grill. (Keep the bowl for the rest of the vegetables.) As the pepper chars and blisters, use grilling tongs to turn it frequently so that the pepper gets charred on all sides-this will take 8 to 12 minutes. Remove it from the grill and immediately place it in a small paper or plastic bag. Close the bag and allow the pepper to steam for at least 5 minutes. Remove the pepper from the bag and use a spoon or gloved finger to remove the skin. Remove the seeds and stem, cut the roasted pepper into strips, and transfer them to a large bowl.

Place the carrots in the same bowl used to season the bell pepper. Toss them with 4 teaspoons of the oil, 1 teaspoon of the salt, and ½ teaspoon of the pepper. Place them on the grill (perpendicular to the grates).

Add the squash and zucchini to the bowl you used for the carrots and toss with 1½ teaspoons of the canola oil, 1/2 teaspoon of the salt, and 1/4 teaspoon of the pepper. Once the carrots have been on the grill for 4 to 5 minutes, they should be brown and wrinkled and their thin tips might be almost black. Flip them. Place the squash and zucchini on the grill. Cook for another 5 to 6 minutes. Toss the asparagus and scallions with the remaining 1½ teaspoons oil, ½ teaspoon salt, and 1/4 teaspoon pepper. Place the asparagus and scallions on the grill, turning and rotating so that they cook evenly. Once they have a slight char and wrinkled skin, after 6 to 8 minutes, begin removing the vegetables as they are done and place them in the bowl with the roasted peppers. Toss the vegetables with the vinaigrette and transfer to a serving platter. Sprinkle with the rib rub and serve warm.