In a large saute pan over medium-high heat, add the oil. When the oil is hot add the tilapia and saute until golden on 1 side. Flip them over and finish cooking on the other side. Remove the fish from pan to a plate and keep warm.
Deglaze the saute pan with the water and stir in the chili paste. Carefully transfer the mixture to a blender. Add the 2 teaspoons salt, the raisins, and the 1/2 corn tortilla and puree until very smooth.
Briefly toast the remaining 8 tortillas over an open flame and lay 2 tortillas on each of 4 plates. Break up the fish and divide it evenly among the tortillas. Spoon the mole sauce over the fish, top with the shredded iceberg and garnish with the cotija cheese. Serve.