In a statement yesterday, Khan said he had instructed mayoral agency Transport for London (TfL) to "take forward" a new extension of the Docklands Light Railway (DLR) from Gallions Reach towards Thamesmead.
A spokesman for the mayor said that this meant that TfL would be "taking forward feasibility work" on the scheme.
In the statement, Khan said that the new crossing would help support development of "around 17,000 new homes" across the London Borough of Newham and the Royal Borough of Greenwich in the next 10 years, and also help improve air quality by improving conditions for walking and cycling, and encouraging Londoners to take public transport.
The statement also said that Khan had asked TfL "to look at developing a new ferry between Canary Wharf and North Greenwich, which will help support new developments on the Greenwich Peninsula and the Isle of Dogs, as well as reduce demand on the Jubilee line at key times".
TfL is also "looking at the case for the extension of the London Overground from Barking Riverside across the Thames towards South East London", the statement added.
Elsewhere, the statement said that the mayor has asked "for the acceleration of the new pedestrian and cycling bridge linking Rotherhithe and Canary Wharf".
It said that a procurement process would be held next year and subject to funding, availability of land and relevant approvals, the new bridge could be open by 2020.
Khan also announced that a series of "enhancements" would be made to the proposals for the Silvertown tunnel which is due to begin its examination by the Planning Inspectorate this month.
These include a "clear commitment within TfL’s business plan to support the new buses through the tunnel" and a commitment to "look at providing a bespoke cycle-bus which will carry cyclists and their bikes through the tunnel on a turn-up and go basis".