Remove tough ribs from kale. Layer kale leaves on top of one another and roll into tube. Chop tube to make strips, and wash the strips by placing in bowl of water, and letting sit until dirt falls to the bottom of the bowl.
Heat oil and garlic in skillet over medium heat 6 to 8 minutes, or until garlic starts to brown or turns golden, stirring occasionally. Set garlic aside on plate.
Shake kale dry.
Add a few handfuls of kale to pan, and stir until kale wilts. Add remaining kale a few handfuls at a time; sauté 5 minutes, or until tender, stirring occasionally.
Transfer kale to colander to drain, pressing to remove excess liquid. Return kale to pan, and stir in dates and vinegar. Heat 2 to 3 minutes, or until heated through.