Heat oil in a pot or wok, add the onion, and sauté until the onion is soft and translucent. Add the lettuce and sauté for a few seconds.
Add the peas, salt, black pepper, and sugar. Stir well, cover, and cook over medium-low heat for about ten minutes, until the peas soften. Stir occasionally.
If there is any liquid left in the pot, remove the lid, increase the heat to medium, and cook for a few more minutes until the liquid evaporates. Remove from heat.
Add the green onions, roasted red pepper, and mayo, and stir well. Serve as is, as a side dish, or as a main course with vegan hard-boiled eggs (recipe coming soon).