The longer you let the vinaigrette stand, the spicier the kick from the chiles. And we know the dressing calls for a lot of thyme, but we loved the result.
Cooks' notes:
•Vinaigrette can be chilled, covered, up to 1 week. Bring to room temperature and stir before serving.
•Pickled watermelon rind can be made 1 week ahead and cooled completely, uncovered, then chilled, covered.