Whisk together the creme fraiche, vinegar, honey, salt and pepper until smooth. Stir in the tarragon, then the goat cheese crumbles. Refrigerate until ready to use.
Preheat the grill to high and prepare for direct grilling.
Lightly brush the ears of corn with olive oil and lay them on the grill. Cook, turning every few minutes, until all sides are slightly charred (about 10 minutes). Remove from the flame and allow the ears to cool.
Use a small, serrated knife to remove the kernels from the ears. Keep the ears near horizontal to the cutting board as you slice from stem to tip, and go slowly. The goal is to remove the kernels in connected strips. As a small strip is freed from the cob, stop slicing and gently transfer it to the cutting board.
Line a platter with the arugula, then gently arrange the corn strips on top. Scatter the serrano slices, and sprinkle the chopped cilantro over the top.
Spoon a portion of the tarragon creme dressing lighlty over the salad, making sure to let colors of the salad peek through. Finish the salad with a pinch of salt and a few grinds of black pepper. Serve the remaining dressing on the side at the table.