In a small bowl, whisk together cornstarch, baking powder, salt, pepper and garlic. Set aside.
Cut salmon into ¾" boneless cubes and place in a medium or large bowl.Preheat a heavy-bottomed frying pan or large skillet over high heat.
Pour cornstarch mixture over salmon cubes and gently toss to coat.
Add vegetable oil to the pan. Once it's at the smoking point, add salmon cubes in a single layer. Keep space between the salmon pieces and don't overlap. Cook in 2 separate batches if needed.
Once the first side is golden brown, flip the marinated salmon cubes. Continue to flip until each side is crispy, approximately 5 minutes total. Turn the heat off and tip pan to one side and slide a metal pot lid under. Using the spatula, slide the crispy salmon bites to the high side of the pan so any excess oil can drain off for 1-2 minutes.
Remove from pan with a slotted spatula and serve cooked salmon bites immediately or place on a wire cooling rack to keep them crispy until serving.
Notes
Use the best salmon or fish you can. It is the star of the dish and fresh tasting seafood is always the best.