Heat oil in a non-stick skillet over medium-high heat. Meanwhile, mix the salmon, 2 tbsp Astro Original yogourt, breadcrumbs and salt and pepper together. Shape into 4 - ¾-inch patties.
Sear the patties on both sides for 4 minutes or until golden, about 8 minutes total.
Meanwhile, top buns with lettuce, tomato and red onion. Once patties are cooked place on top of the onion and add a dollop of Astro Original yogourt. To each burger add a pinch of lemon zest and freshly ground black pepper.