Assuming that the piano being played was tuned normally (equal temperament, these days), it probably would not strictly be possible to emulate most type of Indian/Indonesian/Oriental scales. However, there are tonicless scales and intervals that sound 'Eastern' to Western ears, even though they may not be authentic, such as the pentatonic scale (whole-whole-whole-minor 3rd-whole), whole-tone scale (whole-whole-whole-whole-whole-whole) or scales that employ the interval of the augmented second, a traditionally 'forbidden' melodic interval in Western Classical Music, or even tritones (augmented fourth/diminished 5th, 'devil's interval'

. What I think the Western ear finds most 'Eastern' sounding is a *floaty* suspension of tonality while still being pleasing to the ear; one does not feel any gravitational pull toward any one note, but the music seems to proceed without goal yet never seems boring.
Some insight into the mentality of _emulating_ this 'Oriental' sound can be gained by studying the music of Debussy and Satie, who explored a number of non-western scales and modes and ostensibly used oriental settings and titles as thematic substance. It's not necessary to learn these pieces or memorize them, by any means. Simply looking at the intervals that make up the scalar passages and the type of harmony used will provide the base patterns and modes for many of your own improvisations; practice the scales you find and transcribe them to every note (for many of these 5 or 6 note scales, there are significantly less than 12 scales possible) and study the chords that are used against these scales and try to explain their function inside and outside of the diatonic system; sometimes what sounds 'Eastern' can be explained within a portion of tonality (the pentatonic scale is a subset of the major scale) but other scales simply are not diatonic at all and the harmony is internally consistant but not necessary compliant with tonal harmony.
Some 'Eastern' themed Piano pieces to play and/or study:
Debussy:
Reverie Suite Bergamasque Estampes (especially Pagodes) Reflet dans l'eau Et la lune descend sur le temple qui fut (Very good example) Danseuses de Delphes Voiles La fille La Cathedral engloutie (Another very good example) Canope
Satie:
Gymnopedies Gnossiennes [Satie's piano pieces here contain easily discernable RH scales in these very melodic works, and relations between these scales and the unconventional LH chordal accompaniments are an easy way to get some ideas. Satie works all Early Int.]
Good luck,