Start with the vinaigrette: In a small bowl, mix together the Dijon, balsamic, salt and pepper. While whisking, drizzle in the olive oil and mix well to emulsify the mixture. Set aside.
For the pear-topped toasts: Halve each pear and scoop out the core. Cut each half lengthwise into slices about 1/2 inch thick (about 5-6 slices). Using 1 TBL olive oil, brush the pears with oil. Place a cut side of the pear down on a grill or grill pan over medium-high heat and grill until the pear has grill marks and the sugar has started to caramelize, about 2 ½ – 3 minutes. Flip pears and grill another 2 minutes more. Remove from heat and allow to cool slightly.
Meanwhile, using 1 TBL olive oil, lightly brush the slices of bread. You can put these in the oven to broil, but I recommend using a stovetop grill. Using a stovetop grill or large pan, grill both sides just slightly on a medium-high heat, just about 1 min per side. This makes the bread crispy on the outside and chewy on the inside. Once toasted, set aside.
Toss the frisée or arugula with 1 ½ tsp. of the cranberry pear vinaigrette and season to taste with salt and pepper.
Brush one side of the toasted bread with some of vinaigrette, then top with the frisee/arugula and grilled pears. Sprinkle with crumbled cheese and top with bacon and/or walnuts. Drizzle any remaining vinaigrette on top of the assembled toasts. Serve immediately.