Heat oil in a large nonstick skillet over medium-low heat.
Add peas and stir to coat with oil.
Cover and cook, stirring once or twice, until beginning to brown, about 4 minutes.
Stir in mint and cook for 30 seconds.
Add lettuce, cover and cook, stirring once or twice, until wilted, 1 to 2 minutes.
Remove from the heat and season with salt and pepper.