Combine the vinegar, sugar, honey, bourbon and 1 teaspoon salt in a saucepan over medium heat. Bring to a simmer, stirring to dissolve the sugar and salt. Set aside to cool.
Combine the cucumbers and onion in a large bowl. Pour the vinegar mixture over the top and let marinate in the refrigerator until icy cold, 3 to 4 hours. When ready to serve, add the mint and toss to combine.