Wash and dry squash. Slice squash in 1/4 inch or less slices and spread on a platter. Lightly sprinkle salt over slices.
In a large cast iron skillet add enough oil to make it about 1" from the bottom and use medium high heat. If you don't have a cast iron skillet -- however you fry will be fine. In a medium bowl add cornstarch, flour, onion powder. and stir with a fork. Slowly add beer and keep stirring. Stop pouring beer when you have the consistancy of cream.
Pat squash dry (salting squash causes squash to sweat) Dip squash into batter and fry in oil. Put enough slices without touching, and turn after about 1-2 minute or until very light brown. Drain on paper towels and serve. I have soy sauce for dipping.