Cut the roots off the pea shoots and slice them in half. Trim the roots of the shimeji mushrooms and separate them into small clusters. Mince the garlic.

Bring a pot of water to a boil, add the spaghetti, and cook 1 minute less than the package instructions. Drain the water.

Heat olive oil in a frying pan, add garlic, shimeji mushrooms, and red chili. Stir until fragrant, then add the tuna (including its liquid) and sauté for 1–2 minutes.