Combine tomato, onion, jalapeño, garlic and salt in a medium bowl; mix well (To make salsa ahead, prepare to this point; cover with plastic wrap and chill, for up to 1 day, until ready to serve.) Stir in cilantro.
Prepare grill. Put ground beef, tomato sauce, bread crumbs and egg whites in a large bowl. Mix with hands or a wooden spoon until well blended. Divide mixture into 4 portions and pat into ovals about 2/3 inch thick.
Grill meat loaves over medium flame, turning once or twice, until nicely charred and cooked through, about 15 minutes.
While meat cooks, slice potatoes 1/4 inch thick; rinse and pat dry. Brush potato slices on both sides with olive oil and grill, turning once, until golden and crisp, about 12 minutes. Sprinkle with salt.