This is apparently something that normal people know how to do, and I just figured out the ‘knack’.
First, bend over at the waist so that your face, covered in cleanser or clay mask, is close to the sink. This requires your feet to be kind of far from the sink. Then cup the water in your hands and make sure your elbows are above the level of your hands. This is kind of an awkward position. Bending over some more, so that your face is almost in the sink, wash your face with the water.
Some troubleshooting, if you still aren’t getting it, make sure to move your feet back more, then bend at the waist, then hunch over. The primary motion should be at the waist. I know that your shoulders will be uncomfortable at first but it takes a while to get ‘the knack’. It is a challenge like riding a bike, which is still something I cannot do properly. But do not feel bad if you cannot get it. I have a feeling that most people cannot, but unfortunately people who are clumsy are heavily penalized by ‘normals’.
BTW as a liberal and anti-authoritarian, I am glad that although fireworks are technically banned in my area, people have broken into the housing project next door to do fireworks off the roof.