Preheat oven to 350°F. Line a 11 x 16-inch baking sheet with foil, and spray with non stick spray. Lay the matzo crackers down in a single layer, arranging them to leave no gaps between the crackers.
Place margarine in a small saucepot over medium heat. Cook until melted and bubbly; add the brown sugar, and stir constantly while heating. Let the mixture bubble for 2–3 minutes. Remove from heat, and add in the vanilla extract. Pour over the matzo crackers and spread evenly over top. Place in oven for 5 minutes, or until toffee is bubbling.
Remove from the oven, and sprinkle chocolate chips on top of the hot toffee. Smooth with a knife or spatula, over the entire sheet. Sprinkle with the toasted hazelnuts and sprinkle with salt. Cool in the refrigerator, until chocolate is hard. Then cut into squares.