Rinse the cooked white rice under water to remove stickiness and drain well.

Season the salmon fillets with salt and pepper, cut into thirds, and lightly coat with all-purpose flour.

Mince the onion, slice the garlic, trim the shimeji mushrooms, and chop the parsley.

Heat half the olive oil in a pan over medium heat, cook the salmon until browned on both sides for about 5 minutes, then remove.

Wipe the pan clean, add the remaining olive oil and garlic, and cook over low heat until fragrant. Add onion and mushrooms, sauté over medium heat until the onion becomes translucent.

Add the rice and diced tomatoes, mix well, then return the salmon to the pan. Season with salt and black pepper, and mix gently.