Cook kale in a 6-quart pot of boiling salted water (1 1/2 tablespoons salt for 4 quarts water), uncovered, until almost tender, 5 to 7 minutes.
Drain in a colander, then immediately transfer kale to an ice bath to stop cooking. When kale is cool, drain but do not squeeze.
Cook garlic in oil in same pot over medium heat, stirring, until fragrant, about 30 seconds.
Add kale, dried cranberries, 3/4 teaspoon salt, and 1/8 teaspoon pepper and cook, tossing frequently with tongs, until kale is heated through and tender, 4 to 6 minutes.
