By 'off the hotel beach' do you mean exactly that, or would a hotel with jetty to get you to the seaward side of a reef be acceptable. In many places the reefs are close in and fall away fairly quickly so you'll find coral walls. As doe said - Nuweiba (Hilton) has a good entry of a sandy beach, snorkelling is OK but not the best; whilst a little way up the beach (Swisscare) has a beautiful sandy beach with a very good fringing reef and shallow lagoon but you do need to thread your way through to the seaward side to see many fish.
Further south (Sharm etc) you'll find more places with easy access to good snorkelling off the hotel jetties, but stright into water where you'll be out-of-depth.