Preheat oven to 375°. Separate crescent rolls into 4 rectangles; press diagonal perforations to seal.
Combine Hellmann's® or Best Foods® Real Mayonnaise with mustard in small bowl.
Spread about 1 Tbsp. Mayonnaise mixture on each rectangle, leaving 1/2-inch border around edge. Top right half of dough with ham and cheese, folded to fit. Fold other side of dough over filling to form squares; press edges with fork to seal. Arrange pockets on baking sheet.