Cut the tops off the strawberries. Divide the red bean paste into 6 equal portions and cover each strawberry with one portion of the red bean paste. Set the berries aside.
In a microwave-safe bowl, whisk together the glutinous rice flour and the powdered sugar. Then, whisk in the water until a batter forms.
Cover the bowl with a plate and microwave the mochi batter on high heat for 1 minute. Take the bowl out and stir the dough using a wet spatula.
Place the bowl back in the microwave and cook the dough for another minute. Take it out and stir it again. The dough should be almost translucent, and much more firm and sticky.
Place the bowl back in the microwave and microwave the dough for another 30 seconds. Once done, the Mochi dough should be translucent and very sticky. If it hasn't quite reached that stage, microwave the dough for a final 30 seconds.
Place a large square of parchment paper on the counter and sprinkle 1 tablespoon cornstarch on top. Place the mochi dough on the cornstarch, then sprinkle the other tablespoon cornstarch on top of the mochi dough. Roll the dough out, until it's roughly ¼-inch thick. Use a 3-3 ½-inch diameter cookie cutter to cut 6 circles from the dough. These should be large enough to completely wrap around the berries.
Place the dough circles in the fridge for 5 minutes to chill. Take them out, then one at a time, place a strawberry in the center of the circle. Wrap the circle around the berry and pinch the ends together to seal the berry within the mochi dough.
Serve the mochi fresh, and store at room temperature in a sealed box for up to 2 days.