Bring water to a boil in a medium saucepan. Add barley and cook, covered, for 10 to 12 minutes, or according to package directions. Remove from the heat and let stand, covered, for 5 minutes.
Rinse the barley under cool water and transfer to a large bowl. Add snap peas, parsley, onion, oil, lemon juice, salt and pepper and toss to combine.
1 starch, 1 vegetable, 1 fat