In a large bowl, whisk together the flour, baking powder, and salt.
Add the eggs and mix well. Gradually add the water, a little at a time, mixing until a dough forms. Knead the dough for 5-7 minutes, until smooth and elastic.
Cover the dough and let it rest for at least 30 minutes.
Divide the dough in half. Roll out one half into a thin rectangle and cut into thin strips, then cut crosswise into shorter pieces.
Heat vegetable oil to 350°F (175°C) and fry the dough strips in batches until golden brown and crispy. Drain on paper towels.
In a pot or wok, combine sugar, maltose, and water. Cook over medium heat until sugar is dissolved and syrup thickens to the soft-ball stage.
Reduce heat to low, add fried dough strips to the syrup, and toss to coat evenly.
Grease a baking pan, pour in the coated dough, and press firmly and evenly. Sprinkle with sesame seeds if using.
Let Sachima cool completely in the pan, then cut into squares or rectangles.