Place wheat berries in a saucepan on medium-high heat, and toast for about 3 minutes or until they start to turn golden, stirring frequently.
Add water and ½ teaspoon salt and bring to a rolling boil. Turn heat down to low, and simmer wheat berries for about an hour or until tender.
While wheat berries are cooking, mix together lemon juice, olive oil, herbs, ¼ teaspoon salt, and pepper for dressing. Set aside.
Drain wheat berries when tender, and toss with dressing while warm.
Cut the zucchini and summer squash into long slices, approximately ¼ inch thick.
Slice the onion into ¼ inch thick rounds. Cut the sweet pepper quarters lengthwise and remove the core and any thick inner membranes and seeds.
Brush all vegetables with olive oil, and grill until onions, zucchini and summer squash are tender, and outside of peppers are charred. About 3-6 minutes on each side.
Let vegetables cool a bit until they are easy to handle Cut all vegetables into 1-2 inch pieces and toss with wheat berry/lemon dressing mixture.
Sprinkle Feta cheese if desired, and toss lightly.
Serve at room temperature.