Wash the mushrooms and carrots thoroughly, then slice them into bite-sized pieces.
Wash the lettuce and cucumber, and cut them into appropriate sizes.
Heat olive oil in a pan and lightly sauté the mushrooms and carrots.
Place the sautéed mushrooms and carrots, along with the vegetables, into a bowl.
Add salt, pepper, lemon juice, and olive oil, then gently toss everything together.