Rinse farro or wheat berries. Place in saucepan with about 1/4-1/2 teaspoon salt. Cover with about 2 inches of water. Bring to a boil. Reduce to a simmer, cover and simmer for about 1 hour. (to desired tenderness).
In the meantime, defrost peas. Place in colander.
Drain and rinse farro and rinse with cold water (over peas that are defrosting); drain.
Combine farro, peas, salt and pepper in a large bowl. Add watermelon cubes and parsley and gently toss to combine. Top salad with cheese.