Heat the oil in a Dutch oven or large pot over medium heat until shimmering.
Add the ginger and cook, stirring constantly, until fragrant, about 30 seconds.
Add the spinach in 2 to 3 batches, along with the salt and pepper in the first batch.
Use tongs to toss the leaves after each addition.
Cook, stirring occasionally, until wilted, 3 to 4 minutes.
Remove from the heat and stir in the lemon juice.
