The combination of succulent fruit and peppery arugula is especially effective in salads, and the variations are endless. The blue cheese is a deluxe addition; its rich pungency and creamy texture are an excellent counterpoint to the sweetness of the pears and the spice of the greens.
Position a rack in the lower third of the oven and preheat to 475 degrees F. Line a baking sheet with parchment, Silpat, or aluminum foil and set aside.
Place the maple syrup in a bowl and add the pear wedges, stirring gently to coat all surfaces. Remove the pears from the syrup with tongs and transfer to the prepared baking tray. Reserve any maple syrup still in the bowl.
Season the pears lightly with salt and pepper, and roast until the fruit is browned on the bottom, 10 to 15 minutes. Turn the slices with a spatula or tongs, and continue cooking until the pears are tender and golden brown, 5 to 7 minutes. Remove the tray from the oven and let the pears cool slightly.
Make a vinaigrette by combining the vinegar, mustard, and olive oil in a small glass jar. Shake vigorously to combine. Season to taste with salt and pepper, then add a teaspoon of the reserved maple syrup to the dressing, or more to taste.
Just before serving, place 2 tablespoons of the vinaigrette in a large bowl. Add the arugula and toss to coat the leaves. Add more dressing sparingly, if desired (leftover dressing can be refrigerated for up to 4 weeks).
Arrange the greens on a platter, and add the blue cheese and roasted pears. Serve immediately.