Remove hull from strawberries. Slice 1/4 inch thick, lengthwise. Slice apples as thinly as possible. You'll want 4 or so slices of each apple.
Spread Nutella on one slice of bread and sprinkle with flax and chia seeds. Press strawberries gently into sandwich, then top with apple slices.
2 slices sourdough bread, 2 teaspoons Nutella, 2 teaspoons flax seeds, 2 teaspoons chia seeds, 2 strawberries, 1/3 Granny Smith apple, 1/3 Gala apple
Place the second slice of bread atop the first and cut the sandwich in half for easy eating. Garnish with another strawberry for fun, if you so choose.