Heat the oven to 350°F and place the pecans on a rimmed baking sheet. Toast for 8-10 minutes until they darken by a couple of shades of brown and turn fragrant. Remove from the oven and cool.
Stir the mustard, honey, and vinegar together in a medium bowl. Slowly whisk in the olive oil to emulsify it with the vinegar mixture. Add a pinch of salt to taste and set aside.
Tear the lettuces into bite-sized pieces and place in a large salad bowl. Core the pear and cut into thin slices and tuck the slices into the lettuces. Sprinkle the cheese over the salad, followed by the cooled pecans. Drizzle with dressing to taste, dust with flaky salt, and serve.