Heat a skillet with a little olive oil. Add the minced garlic and cook until fragrant.
Add spinach and season with salt, pepper, red chili pepper flakes (if using), and lemon juice and saute spinach for 2-3 minutes over medium-low, until wilted. Adjust seasoning if needed.
Serve the sauteed lemon garlic spinach immediately off the pan, or transfer to a serving plate.