Heat 4 teaspoons olive oil in a small saucepan over medium-low heat. Add 1 thinly sliced garlic clove; cook until garlic begins to turn golden, stirring frequently. Remove from heat. Discard garlic; stir in 1/8 teaspoon salt. Heat a grill pan over medium-high heat; coat pan with cooking spray. Add 4 (1/2-inch-thick) slices ciabatta bread to pan; cook 2 minutes on each side or until lightly browned. Brush one side of each slice with garlic oil.