Wash and wipe dry zucchini. Trim ends and slice lengthwise, saving outer edges for soup. Brush both sides with olive oil and garlic salt and pepper. Let sit for a few minutes, then barbeque on medium heat for about 10 minutes (flipping once or twice). Alternatively, place in a single layer in a wide pan on stove. Medium to high heat, 10 minutes or so, flipping a couple of times.