Brush both sides of the bread with olive oil. Place 4 slices of bread on a baking sheet and place 2 slices of fontina, 4 slices of pepper, artichokes and arugula on each slice of bread. Top each slice with the remaining 4 slices of bread and grill for 3 to 4 minutes on each side, or until golden brown and the cheese has melted.
Black Olive Mayonnaise: Place all ingredients in a food processor and process until smooth. Serve with sandwiches.