In a medium bowl, whisk eggs, salt and pepper. Set aside.
Pour canola oil into a large non-stick frying pan. Place over medium-high heat. Add zucchini and sauté for about 2 to 3 minutes. Add tomatoes and garlic. Continue to cook 1 to 2 minutes longer. Spread vegetables in an even layer in the pan. Pour egg mixture over top of the vegetables. Reduce heat to low and cook about 2 minutes. Cover pan and cook about 5 minutes, until top of egg mixture has set. For a golden brown top, place frittata under broiler for 1 to 2 minutes. Slide frittata onto a large plate and cut into 8 wedges.
Meanwhile, toast bread. Place 4 pieces of toast onto a cutting board. Spread each one with approximately 1 tbsp (15 mL) tomato pesto. Arrange 2 frittata wedges over each piece of toast. Top with arugula. Place 4 remaining pieces of toast over sandwich bottoms and serve immediately.
If frying pan handle is not oven proof, cover completely with double thickness of aluminum foil.