Mash garlic clove and rub on the bottom and sides of fondue pot and a medium, heavy-bottomed pot. Pour wine in heavy-bottomed pot and bring to just below a simmer. Toss cheese with cornstarch. Reduce heat to medium-low and add cheese in 2 additions, stirring gently with a wooden spoon until melted. Stir in Kirsch and transfer fondue to fondue pot.