Pull the kale leaves from their stems. Coarsely Chop the leaves. Rinse them but do not dry.
Heat oil in a large saute pan over medium-high heat until shimmering.
Add the garlic and red pepper flakes. Cook until fragrant (about 1 minute, do not let the garlic brown).
Add the kale (a few handfuls at a time). Stirring until it starts to wilt.
Stir until all the Kale is added.
Stir in salt and pepper.
Cover and cook, stirring occasionally until kale is tender about 5 minutes.
Remove from heat. Stir in the lemon juice and serve.