To make the praline, lightly oil a large baking sheet. Toss the pecans with the salt and cayenne in a small bowl. Place the sugar in a heavy skillet or saucepan and cook over medium heat, stirring gently, until the sugar starts to melt. Stop stirring and continue cooking, swirling the skillet or pan often, until the sugar cooks to a dark golden caramel. Add the pecan mixture and carefully stir to coat the nuts with caramel. Pour onto the baking sheet and spread evenly with a knife. Cool completely. Crack the praline into pieces, then finely chop on a cutting board.
To prepare the dressing, whisk the mustard, vinegar, salt, and pepper in a small bowl. Slowly whisk in the olive oil to form a smooth dressing.
Arrange the arugula in the center of a large serving bowl. Sprinkle on the cheese, cherries, and praline. Toss with just enough of the dressing to thoroughly coat the leaves.