In a small bowl, combine warm water, yeast, and sugar. Stir gently and let sit for 5-7 minutes until foamy.
In a large mixing bowl, whisk together flour and salt.
Add the yeast mixture and olive oil to the flour mixture. Stir with a wooden spoon until a dough forms.
Turn the dough onto a lightly floured surface and knead for 8-10 minutes until smooth and elastic.
Place the dough in a lightly oiled bowl, cover with a clean kitchen towel, and let rise in a warm place for 1 hour or until doubled in size.
Preheat your pellet grill to 450°F with the grill lid closed, allowing it to reach a stable temperature.
Lightly oil a 10-inch cast iron skillet with olive oil.
Punch down the risen dough and press it evenly into the bottom and slightly up the sides of the cast iron skillet.
Spread pizza sauce evenly over the dough.
Sprinkle shredded mozzarella cheese over the sauce.
Distribute pepperoni slices, black olives, and green bell pepper evenly over the cheese.
Sprinkle dried oregano and crushed red pepper flakes (if using) on top.
Place the cast iron skillet on the pellet grill grates and close the lid.
Cook for 15-20 minutes, checking after 15 minutes, until the crust is golden brown and the cheese is melted and bubbly.
Carefully remove the skillet from the grill using heat-resistant gloves.
Let the pizza cool for 3-5 minutes before slicing and serving.