Preheat oven to 400F. Grease or line a baking sheet with parchment paper or silicone baking mat.
Combine 1 tablespoon ground flaxseeds with 3 tablespoons of warm water. Let it sit for at least 5 minutes until it thickens and turns into a gel-like consistency.
Rinse and drain the salmon to remove excess sodium. Pat dry.
Cook the vegetables in a lightly oiled skillet over medium heat for several minutes, until softened. Set aside to cool.
In a large bowl, combine all the ingredients until well-incorporated.
Scoop a large spoonful and using your hands shape into firm balls. You will end up with 14-16 balls. Then flatten slightly using your palms.
Place on prepared baking sheet and bake for 10 minutes, flip and bake for an additional 5-8 minutes.
Combine all the ingredients for the mango yogurt sauce.
Due to the variation in moisture content of canned goods, your cakes might not hold together well. If so, first try adding a bit more breadcrumbs. If that doesn't work, add another flax egg, although I've never had to do this.
Remove extra moisture: Pat the salmon dry after rinsing. COOK the veggies! Raw vegetables hold a lot of water, which will get released during cooking. It will also add more flavor so definitely don't skip this step!
Shape the mixture FIRMLY into balls first then flatten slightly between your palms.
Transfer to an airtight container and keep in the fridge for up to 5 days or in the freezer for up to 3 months.