Cook the rice like you would pasta: Bring a large pot of lightly salted water to a boil. Add the rice and cook until tender, about 10 to 15 minutes. Do not overcook or undercook it; the rice should be soft all the way through but should not be starting to “explode” on the ends of the grains.
Chop the Vegetables: While the rice is cooking, wash and dice the shallots, bell pepper, celery, and carrots. Set aside.
Make the Dressing: Add the parsley, salt, pepper, olive oil, and lemon juice to a small bowl and whisk to combine.
Line a baking sheet pan with a kitchen towel. Drain the rice and rinse it quickly under cool water (don't let it get cold), then spread it over the kitchen towel. Cover with another kitchen towel and gently pat dry.
While the rice is still warm, transfer it to a large salad bowl and add the dressing and vegetables and toss gently with a large spatula. Taste for salt.
Refrigerate for 30 minutes to allow the flavors to develop.
Serve cold or room temperature.