Mix lukewarm water, sugar, and yeast in a small bowl. Let stand until yeast softens and bubbles slightly, about 5 minutes.
Sift together flour and salt in a large bowl.
Pour yeast mixture over flour mixture and knead until dough is smooth and elastic, 5 to 7 minutes. Cover bowl with a clean cloth and let dough rise until doubled in volume, about 45 minutes.
Pinch off a piece of dough about the size of a tennis ball; roll until smooth. Flatten ball of dough until it is palm-sized; set aside on a floured work surface. Repeat with remaining dough.
Heat oil in a deep-fryer or large saucepan to 350 degrees F (175 degrees C).
Fry in hot oil, 2 to 3 pieces at a time, until golden brown, about 3 minutes per side. Drain on paper towels.