Preheat the grill. Slice the bread at an angle into 20 thin pieces. Using 3 tablespoons olive oil, brush both sides of each slice of bread. Place the bread slices on the hot grill and toast, about 2 minutes on each side, or until golden.
Cut each slice of ham in quarters. In a small saute pan, add the remaining tablespoon olive oil and cook the ham until crispy. Remove the ham to a paper towel to remove the excess oil.
While the bread is still warm, rub a clove of garlic on each slice of bread. Cut the top off the tomatoes and rub the tomato on the slices of bread. Drizzle olive oil on each piece and sprinkle with kosher salt. Top with a piece of ham.