In a small saucepan, combine the water and quinoa. Bring to boiling; reduce heat. Cover and simmer about 15 minutes or until water is absorbed. Remove from heat and set aside.
Meanwhile, in a large bowl, combine sweet pepper, tomatoes, garbanzo beans, green onions, parsley, and mint. Add the cooked quinoa; mix well. Add lemon juice; toss well to mix. Season to taste with salt and black pepper. Cover and refrigerate for 2 to 4 hours before serving.