Place the cream cheese, Swiss or mozzarella cheese, chopped shallot, mustard, Worcestershire sauce and salt in the bowl of an electric mixer. Mix to combine.
Line a baking pan with parchment paper or waxed paper. Divide the cheese mixture into 16 balls. Form the balls into teardrop shapes. Cover the cheese shapes loosely with plastic wrap and refrigerate 1 hour or more.
Remove the cheese shapes from the refrigerator. Place two pieces of black olives on each mouse to form eyes. Place one olive piece on each for a nose. Place two almonds upright to form the ears. Use a toothpick to make a small hole in each mouse to insert the chive tail.