Shred sweet potato and onion.
Rinse the potato under cold water, then strained them with a colander. Place a cheesecloth over the potatoes, and squeeze the potatoes to release as much liquid as possible. Discard liquid.
In a large bowl, combine sweet potatoes, onions, eggs, sugar, matzo meal, cinnamon, gently mix well by hand.
Heat oil in a large heavy skillet to 375 degrees. Scoop from the mixture (about 3 ½ ounce portions) and drop in hot oil. Cook about 2-3 minutes on each side until golden brown. Drain then in a paper towel or resting rack.