Heat a griddle to medium-high heat and lightly oil. Grill pupusas for approximately 5-6 minutes per side, flipping occasionally as needed, until both sides are nicely browned. Serve immediately (or return to baking sheet and store in 350 degree oven until entire batch is completed.)

Cover countertop with a 10-by-10-inch sheet of plastic wrap or parchment paper. Set out a small bowl of water and a small bowl of canola oil. Pinch off 1/2 cup of dough and form it into a ball; continue rolling dough to form 8-10 round balls. Working with 1 ball at a time, dampen hands with water, press dough in between both hands and continue patting to form a disc. Lay disc down on the counter and press dough out into a 7-inch round disc with hands or a rolling pin to approximately 1/4-inch thick. Repeat with other dough balls. Stack tortillas with plastic wrap in between each to avoid sticking.