Bring the barley, water and first 1/2 teaspoon of salt to a boil in a large saucepan. Reduce to a simmer and cook until the barley is tender, 20 to 25 minutes.
Drain and rinse with cold water. Refrigerate if the other ingredients are not yet ready.
While the barley is cooking, make the vinaigrette.
Mix the balsamic and red wine vinegars in a bowl with the mustard, cayenne and remaining salt.
Whisking constantly, slowly drizzle in and incorporate the oil. Stir in the sun-dried tomatoes, the scapes and the shallot. Set aside.
In medium-hot skillet, stirring constantly, toast the sunflower seeds, When the sunflower seeds are lightly toasted, immediately stir in the tamari soy sauce and remove from the heat. Set aside.
Cut the beet greens in fine ribbons: Stack 6 to 7 leaves, roll them like a cigar and slice the roll very thinly.
Mix the vinaigrette, beet green ribbons, and tamari sunflower seeds into the cooked barley. Drop in the goat cheese chunks, if using, and mix everything very well.
Enjoy immediately or refrigerate and serve within 2 days.