In a 2-cup glass measure, mix 1 cup seasoned rice vinegar and 2 teaspoons broken star anise.
Heat in a microwave oven at full power (100%) until vinegar boils, about 3 minutes.
Pour through a fine strainer into a bowl with 2 cups shredded red cabbage, 1 cup diced (1/4 in.) English cucumber, 1 tablespoon minced garlic, and 1 teaspoon salt; discard star anise.
Mix and let stand at least 10 minutes.
Serve warm or cool, or cover and chill up to 2 days.