Place the grated potato, zuchinni and carrot into a bowl and add 1 egg and cornstarch. Season with salt and pepper to taste and mix until well combined.
Heat the olive oil in a frypan over medium-high heat. Portion the sweet potato mixture into the frypan with a tablespoon. Press down and sauté for about 3 minutes on each side until golden brown.
Once the hash is cooked, beat the remaining eggs and egg whites and stir in the pan to make a scramble. Season with salt and pepper to taste, stirring until cooked.
Mix the Greek yogurt with the lime zest and juice and season with a little more salt and pepper.
Serve the sweet potato hash topped with the lime yogurt, scrambled eggs and smoked salmon.