Turn on the Foreman Grill and let it warm up to around 375° F.
Prepare the halibut: Place the extra-virgin olive oil, lemon juice, salt, and pepper in a baking dish or sealable baggie. Pat the steaks dry.
Place the fish in the dish or baggie and turn to coat with the marinade.
Allow the fish to marinate for 10 minutes at room temperature.
Place the tomato halves, skin side down, on the grill and cook until the skin just blisters. You don’t need to put the top down. This will likely take a minute. Remove the tomatoes and set aside to cool.
Mix the extra-virgin olive oil, vinegar, salt, and pepper in a large bowl.
Brush both grill plates with extra-virgin olive oil or a little butter.
Grill the fish with the top closed for 3 to 5 minutes until the flesh is opaque and flaky in the center.
Grill the lemon slices at the last minute.
While the fish is grilling, mix the tomatoes with the vinaigrette.
Place a handful of arugula on each plate, top with tomato salad, then basil.
Place the fish over the salad and top the steaks with grilled lemon slices. Serve immediately.
Serve wedges of crusty Tuscan bread or gluten free flat bread on the side to soak up the salad dressing and fish drippings and to round out the meal.