Over high heat, bring a large pan of salted water to a boil. Add the pasta, and cook according to package instructions, or until al dente. Drain the pasta, transfer to a serving bowl, cover with a clean tea towel, and let it cool.
When cooled, add the mushroom, bell pepper, spring onion and coriander, and season with salt and pepper to taste.
In a small mixing bowl, whisk together the lemon juice and olive oil until smooth.
Add the oil mixture to the pasta salad, toss well, and serve!