In a bowl, combine the chopped prawns, garlic, ginger, and scallions. Add the soy sauce and sesame oil, then mix well to combine.
Trim the crusts off the bread slices to create clean, rectangular pieces.
Generously spread the prawn mixture over the surface of the bread, leaving a small border around the edges.
Sprinkle the sesame seeds evenly over the prawn topping, pressing them gently to help them adhere.
In a large frying pan or wok, heat the vegetable oil over medium-high heat.
Carefully place the prawn toast, prawn side down, into the hot oil. Fry for 2-3 minutes per side, or until the bread is golden brown and crispy.
Remove the prawn toast from the oil and place them on a paper towel-lined plate to drain any excess oil.
Serve the crispy prawn toast hot, garnished with additional chopped scallions if desired.