Slice the loaf of bread in half horizontally to create two long pieces. Brush the cut side of each half of bread with about 1 Tbsp of olive oil.
Reduce grill heat to medium and place the bread cut-side down on the grill for 1-2 minutes per side. (Note: Watch the bread closely at this stage as it can burn quickly!)
Rub the garlic against the cut-sides of the bread. (The crispy bread essentially grates the fresh garlic.)
Drizzle the top of the bread with the remaining olive oil and then layer sliced tomatoes on top. Sprinkle with sliced basil and sea salt.