Reserve 16 whole olives for garnish. Chop remaining olives; place in medium bowl. Add Cheddar cheese, mayonnaise, cream cheese and red pepper; beat with electric mixer on medium speed until well blended.
Spread about 2 tablespoons cheese mixture on 8 of the bread slices. Top with remaining bread slices. Cut each sandwich diagonally in half.
Garnish each appetizer with 1 whole olive secured with a toothpick or decorative pick.