Using the meat from a rotisserie chicken is a convenient shortcut for making this tempting main course salad. Serve over lettuce and chopped fresh vegetables for lunch, dinner, or picnics.
Rinse quinoa under cold running water and drain. Bring 2 cups water to a boil. Stir in quinoa and a pinch of salt then reduce heat, cover, and simmer until tender and most of the liquid is absorbed,15 to 20 minutes. Uncover and set aside to let cool.
In a large bowl, whisk together vinegar, salt, and pepper. Slowly add the oil, whisking well. Add quinoa and toss to combine. Add chicken, grapes, and almonds and toss again. Serve at room temperature or chilled, if you like.