For the salad: Prepare the ingredients for the grill. Cut the carrots into halves equal in length. Then cut the smaller tip of the carrot into fourths lengthwise and the larger half into sixths or eighths. The key is making the spears all the about the same size. Line up the prepared carrots, corn and pineapple slices on a tray and drizzle with olive oil. Sprinkle all with a pinch or two of salt and a few grinds of pepper. Flip the pineapple rings and repeat the process for them only. Roll and jiggle the rest to fully coat them.
Grill the prepared ingredients. Heat the grill or grill pan to medium-high. Place the carrots, corn, and pineapple rings directly on the grill. Use tongs to tend to the grill. Roll and flip the vegetables until your personal preference for doneness, pulling each off to a tray when done. The carrots are best when charred, caramelized and a bit crispy on the ends, 10 to 12 minutes. Corn is great fresh, so just go for color on all sides, about 8 minutes total. The pineapples are best when slightly charred, but still juicy, about 6 minutes total, flipping once.
Combine the salad ingredients. When the grilled goods are all cool enough to handle, chop the carrots, pineapples and trim the kernels off the corn. Add to a bowl along with the scallions, celery and cucumber.
For the vinaigrette: In a medium bowl, add the pineapple juice, mustard, apple cider vinegar, sugar and liquid smoke and whisk until combined. Continue to whisk rigorously while slowly pouring the olive oil into the bowl with your other hand, or with the help of a friend, nice to have them in the kitchen! Taste the vinaigrette and season with a pinch of salt and few grinds of black pepper.
Dress the salad. Pour the vinaigrette over the bowl then gently toss using tongs. Serve room temperature or chilled.