Melt chocolate chips in the microwave. Spray/lightly oil an 8×8 glass baking dish. Mix the mochiko, water and sugar thoroughly (no clumps). Add melted chocolate chips to the mochiko mixture and mix until thoroughly blended. Pour into the greased dish.
Lay out plastic wrap on a cutting board and dust with the cocoa powder.
Microwave the mixture at 2-3 minute intervals on high until the surface is dry to the touch. Towards the end you may need to do it in 1 minute intervals depending on the power of your microwave. The surface will bubble up some.
Turn out the mochi onto your cocoa powder dusted cutting board. Cut or twist off pieces and roll in cocoa powder dusted palms into somewhat smooth. Dust with a little more cocoa powder and place in a paper muffin cup or wrap in plastic wrap.
Be sure to verify the safety of your chocolate chips.