Heat a large pan over medium high heat, add the 1/8 cup oil and saute red onion until transparent.
Add blanched heart of palm into the pan and lower heat to medium. Continue mixing for at least 10 minutes. Season with salt.
Place sauteed heart of palm in a colander to drain off excess liquid and cool.
Take a piece of spring roll or lumpia wrapper and lay it on a plate.
Fill the center of the wrapper with approximately 2 tablespoons of ubod filling, fold the sides and roll it until it wraps the whole filling.
Seal the edges of the spring roll with the cornstarch mixture.
Pour vegetable oil in a deep frying pan just enough to cover the spring roll; approximately 2 inches.
Heat the oil and deep fry the spring rolls for about 3 to 5 minutes or until it turns golden brown.
Serve with lettuce and spiced vinegar.