To make the dough: In the bowl of a stand mixer fitted with the dough hook (or in a large bowl), whisk the water, maple syrup and yeast together. Let the yeast bloom until foamy, about 15 minutes.
Add in the sourdough discard, whole wheat flour, and sea salt into the yeast mixture.
Mix on low until no dry bits of flour remain.
Slowly stream in the olive oil as you are mixing on low speed.
Continue to knead the dough until the oil is completely absorbed. The dough should start greasy and gradually become smoother and less sticky.
Cover the bowl with plastic wrap and let the dough rest for 15 minutes (if mixing by hand as this will help make it easier to knead). If not mixing by hand, you can continue to knead in your mixer for 5 to 10 minutes or util the dough is smooth and looks elastic.
Transfer to a clean greased mixing bowl and cover with plastic wrap. Set it in a warm place until doubled in volume, about 45 minutes to 1 hour.
Toss the toasted sunflower seeds and poppy seeds in a bowl. Set aside.
Turn the dough out on a lightly floured work surface. Divide the dough into 5 even portions.
Working with 1 portion of dough at a time. Flatten the dough into a rough rectangle, fold the corners towards the center. Turn the dough over, cup the dough and drag it on your work surface in a rounding motion to create a smooth taut surface. Repeat with the remaining portions of dough.
Arrange them in a zigzag pattern in the loaf pan.
Brush the top of the dough with water and sprinkle the seed mixture on top. Press the seeds into the dough with your hands, this will help them from falling off after the bread is baked.
For the second rise, cover the loaf pan with plastic wrap and let the dough rise untouched in a warm place. The dough should fill your pan and rise up to the rim, about 30 to 45 minutes. Preheat the oven to 400°F.
Bake the dough for 10 minutes at 400°F. Without taking the loaf out of the oven, turn the oven temperature down to 350°F and continue baking for another 30 to 45 minutes or until the loaf registers at 200°F when probed with an instant-read thermometer. Allow the bread to cool completely, about 2 hours, before slicing.