In large bowl, combine 1/2 cup warm water yeast and 2 teaspoons sugar; let proof.
Mix the water, salt and flours into yeast mixture.
Knead until smooth (dough will be soft). Use more flour as needed.
Cover lightly and let set in warm place until tripled in size (about 1/1/2 hours).
Punch dough down and let rise again until doubled.
Punch dough down and roll into 2 cylinders.
Cut each roll into 8 rounds.
Lay flat, cover with a towel, and let rest.
Prepare the topping mixture by mixing the oil, poppyseed, onion, and salt; set aside.
Pat the dough into flattened round a little higher in the middle than at the outer edge (each should be about 3 1/2 inches in diameter); place on a lightly floured surface and cover with a dry towel then topped with a damp towel.
Let rise until 1/2 in bulk half proofed (this will take 30 minutes -- don't let over raise).
Press the bottom of shot glass about 1" in the center of each bialy to make a deep indentation.
Spread the topping mixture over the bialys and let rise for 15 minutes more until 3/4 proofed, taking care not to let them over rise.
Preheat oven to 425°F while the bialys are rising.
Carefully transfer the bialys to 2 large 14x17 inch ungreased baking sheets.
Bake on the upper and lower shelves of oven for 6 to 7 minutes; turn and switch the pans on the shelves so they bake evenly 5 to 6 minutes more.