Shell the green peas. Wash and thinly slice the green onions. Pluck the mint leaves from the stems. Zest and juice the lemon. Line the bottom of the steamer basket with parchment paper. Steam the green peas for 5 to 7 minutes. Prepare a vinaigrette with half the lemon juice and the olive oil. Season with salt and pepper. Remove the green peas from the steamer while they are still hot, and then add the green onions and vinaigrette.