Pre-heat a grill or grill pan over medium-high heat.
Meanwhile, whip up the dressing. In a small bowl, combine all the ingredients for the dressing. Season with salt to taste and briefly set aside.
Lightly brush the corn all over with olive oil and season with a little bit of salt. Place the ears of corn directly on the hot grill. Cook for 10-12 minutes, rotating the corn every 2-3 minutes, until the kernels deepen in color and are lightly charred in spots. Let cool slightly, then use a sharp knife to slice the kernels from each cob. Set aside.
Moving on to the romaine. (If you have a large enough grill, you can cook the romaine and corn simultaneously!). Brush the cut-side of the romaine hearts lightly with olive oil. Place them on the grill, cut-side down, and cook for 2-3 minutes, just until grill marks appear and the leaves have softened slightly.
Transfer the romaine to a serving platter or individual plates. Top with the grilled corn, cherry tomatoes, avocado, cilantro and tortilla chips. Drizzle with dressing and serve immediately.