Ouseph claimed the French International title last weekend and outplayed Ukraine No.2 seed Dmytro Zavadsky 21-16, 21-12 in 30 minutes to make it two in a row in Vantaa.
The 26-year-old failed to reach the main draw of the All England Open last month but reached round two of the Swiss Open in his next tournament before his back-to-back titles.
And there was a double celebration for Britain at the Finnish Open as Bankier, who partnered Chris Adcock in the mixed doubles at London 2012, won the women's doubles with Petya Nedelcheva.
Like Ouseph, Bankier was successful at the French International last weekend, this time in the mixed doubles with fellow Scot Robert Blair, before repeating the trick in Vantaa with Nedelcheva.
The Scottish-Bulgarian pairing defeated Danish duo Lena Grebak and Maria Helsbol 21-10, 21-14 also in 30 minutes to be crowned women's doubles champions at the Finnish Open.