In a large mixing bowl, combine the flaked salmon, breadcrumbs, chopped onion, chopped bell pepper, mayonnaise, beaten egg, Dijon mustard, lemon juice, garlic powder, salt, and black pepper. Mix until well combined.
Shape the mixture into small patties, about 2-3 inches in diameter. You should get approximately 8-10 patties.
Heat the vegetable oil in a large skillet over medium heat. Once hot, carefully add the salmon patties to the skillet, cooking in batches if necessary to avoid overcrowding.
Fry the patties for about 4-5 minutes on each side or until golden brown and crispy.
Remove the croquettes from the skillet and place them on a paper towel-lined plate to drain excess oil.
Serve warm with your favorite dipping sauce or a squeeze of lemon juice.