Coat the ears of corn in olive oil, then sprinkle with the salt and chili powder. Use clean hands to evenly coat the corn with the spices.
Heat a grill, grill pan, or cast iron pan over medium heat. Once heated, add the corn and cook until lightly browned all over, turning once or twice while it cooks (7-10 minutes total). Let cool, then cut the corn kernels off the cob.
Make the lime vinaigrette: add the olive oil, apple cider vinegar, lime juice, garlic powder, salt, and black pepper to a small bowl or jar. Whisk or shake vigorously until combined, 30 to 45 seconds, and set aside.
Assemble the salad: add the arugula and corn to a large mixing bowl. Pour the vinaigrette over the salad and toss to coat. Serve immediately for best results (I recommend waiting to dress until right before serving).
