In addition to surface tension, what's responsible for driving ocean waves?

Simple, wind that causes Longshore Drift and Prevailing Wind etc. It also causes waves

Winds drive the ocean waves above and below the ocean's surface.

Explanation:

Ocean waves are the continuous movement of ocean waters that are driven by various factors like wind, salinity, temperatures etc. This flow of ocean water for a large distance determines the climate of many regions on Earth. They form the conveyer belt globally which plays a significant role in climate variation. Wind waves are the gravity waves that is between the atmosphere and the ocean. To maintain equilibrium, apart from all the factors driving ocean waters, in addition to the surface tension, winds drive the waters.