Preheat oven to 400 degrees. Cut off the tops of the garlic heads and place in a baking dish. Mix olive oil and red pepper flakes together and pour over garlic. Cover with foil and bake 40 minutes until garlic is soft. Remove from oven and set aside.
Piadina dough: Measure flour into a large mixing bowl. Make a well in the center and pour in salt, olive oil, water, basil, chives and lemon juice. Using a stand mixer, place dough hook attachment on and set to the lowest speed just to mix ingredients together. Turn to medium and knead the dough 5 minutes, until it forms a ball. This can also be done by hand if a standing mixer is not available, just knead the dough a little longer. The dough is ready when it is smooth and firm. Lightly oil the dough with olive oil, place in plastic wrap and let it rest 30 minutes. Cut the dough into four pieces and roll each out to an eight inch diameter.
Prepare a hot grill on either an outdoor grill, indoor grill pan or cast iron skillet. Lightly oil surface with some vegetable oil or cooking spray to prevent sticking. Place dough rounds on the grill for 1-2 minutes until bubbles form on the surface. Flip and repeat on the other side. Continue with other 3 dough rounds.
In a large bowl, mix together filling ingredients; olives, artichoke hearts and roasted red peppers. Pop out roasted garlic cloves from the heads and smash in a small bowl.
Assemble Piadinas: Brush roasted garlic and red pepper oil over surface of each Piadina round. Place smashed garlic on one half of the round followed by antipasto mixture (about ½ cup). Top with pepperoni (3-4 slices) then, mozzarella ( about 3-4 balls cut in half). Fold Piadina in half and place on a heated pannini grill until the cheese melts. Cut each in half and serve.