Hi,
First, what you can do is remove the "address" view from the checkout workflow.
You can also hide the shipping and payment areas with such CSS code:
.hikashop_shipping_methods, .hikashop_payment_methods{ display:none; }
I would personally leave the cart and coupon views from the second screen so that people can review their cart and potentially add a coupon (if you have coupons) before going to the payment with PayPal.
I don't see what more you can do.
If you want something even simpler, remove all the views except "cart", hide the "finish" button with CSS, and use the PayPal express checkout button. That way, you don't have a checkout at all on your website and it's all handled on the PayPal payment page. But it might not be simpler overall...