To a large skillet set over medium heat, add oil. When oil is shimmering, add garlic and cook until fragrant, about 1 minute. Add spinach and cook, stirring often, until just wilted, 3 to 4 minutes. Remove skillet from heat. Taste and adjust seasoning with salt and pepper. Transfer spinach to a serving platter.
To serve: Toss spinach with lemon zest, lemon juice, and pine nuts. Taste and adjust seasoning with salt and pepper; serve immediately.