The former first minister also suggested the SNP should move from its position in favour of an independent Scotland having European Union membership to having a relationship based on the so-called “Norway model”.
Norway is a member of the European Free Trade Area (EFTA), an arrangement that gives keeps it within the single market from outside the EU.
In a speech to the independence-supporting Business for Scotland organisation, Mr Salmond suggested that membership of EFTA could be a lasting solution for an independent Scotland.
But he also raised the prospect of holding a second referendum after 2021, saying that the 18 months of Brexit negotiations and the three-year transition period would give the SNP time to get its “ducks in a row”.
In the past, First Minister Nicola Sturgeon has indicated that her preference would be for a second referendum before 2021, in case the SNP and Greens lost their independence-supporting Holyrood majority at the polls.
At the dinner, Mr Salmond said: “We have 18 months of Brexit negotiations and after that perhaps a three-year period of transition to get our ducks in a row. We have to offer something which is doable, feasible and speedily deliverable for the European connections of an independent Scotland.”
The former SNP leader, who lost his Gordon seat at the general election, argued that EFTA membership would offer the competitive advantage of the single market.
He added: “In a political sea of uncertainty we would have the advantage of putting forward a defined proposition – an independent Scotland as a member of EFTA with all the economic advantages that confers.”
The possibility of another referendum after 2021 would probably mean the break-up of the UK becoming the dominant issue of the next Scottish election.
Scottish Conservative deputy leader Jackson Carlaw said: “After the slap voters have given the SNP at the recent elections it tried to make about independence, you’d think this would be the last thing the Nationalists would want.
“It also reveals that, even when it pretends otherwise, the issue of separation is never far from the agenda of SNP top brass.”
Previously, Mr Salmond has said EFTA membership could be a staging post on the road to full EU membership. In this speech, however, he suggested it could be a permanent arrangement when he said it could be a “prelude” to full EU membership “if Scotland so wishes”.
But Mr Salmond’s proposal to pursue EFTA membership was not universally welcomed elsewhere in the SNP.
Alyn Smith, SNP MEP, tweeted that “full membership is best for Scotland”.
But a statement released by the SNP’s Michael Russell at the graduation ceremony of the Scottish Association for Marine Science saw the Brexit minister restrict himself to calling for single market and customs union membership.
He said: “The majority of young people voted to remain in the EU. Young people must insist that the chance of a better future is not lost and that therefore the mitigation of the effects of Brexit must be at the heart of policy emanating from Downing Street. The Scottish Government continues to argue that membership of the single market and the customs union is the best compromise.”
When asked about the SNP’s position on Europe and the suggestion that there would be no referendum until 2022 at the earliest, a party spokesman said: “The SNP’s policy is that we should be in the EU – as the people of Scotland voted overwhelmingly in favour of last year.
“The biggest threat to the Scottish economy remains the Tories’ proposals for a damaging extreme Brexit, outside the single market and customs union, hitting jobs, investment and living standards.
“As the First Minister has made clear, Scotland should have a choice on its future when the terms of Brexit are clear.”