In a small bowl, combine masa harina and salt; stir in water. Knead until mixture forms a ball. Divide dough into 16 portions; shape into balls and cover with plastic wrap.
Working between two sheets of plastic wrap, press four balls into 3-1/2-in. circles. On an ungreased griddle, cook dough circles over medium-low heat for 1-2 minutes or until bottoms are lightly set. Turn and cook 2 minutes longer. Remove from the heat; quickly pinch edge of circles to form a 1/2-in. rim. Return to the griddle; cook 2 minutes longer or until bottoms are lightly browned. Remove to wire racks; cover. Repeat with remaining dough.
In a small saucepan, combine chicken and 1/2 cup salsa. Cook over medium-low heat until heated through, stirring occasionally. In a large skillet, melt shortening. Cook sopes over medium-high heat for 2 minutes on each side or until crisp and lightly browned. Remove to paper towels to drain.
To assemble, layer each sope with refried beans, chicken mixture and remaining salsa. Sprinkle with lettuce and queso fresco. Serve immediately.