1. Cook quinoa: In a saucepan, bring water to a boil. Add quinoa, reduce heat, cover, and simmer for 15 minutes. Remove from heat and let it sit, covered, for 5 minutes. Fluff with a fork.
2. Preheat grill to medium-high heat.
3. Toss sliced vegetables with olive oil, salt, and pepper.
4. Grill vegetables for 5-7 minutes on each side until tender and slightly charred.
5. In a large mixing bowl, combine cooked quinoa, grilled vegetables, parsley, and lemon juice. Toss to mix well.