I have a sampled DTFT. If we assume that there isn't aliasing in time domain, what is the best way to reconstruct DTFT from its equidistant samples? I though about Dirichlet interpolation. Do you know if there are other ways to do it? There is any difference between a theoretical approach and a practical approach?
For finite length time domain signals, the DTFT can be obtained from the DFT via interpolation, as explained in this answer. In this case the DTFT can be evaluated at any desired frequency point because it is expressed as a function of a continuous frequency variable.
If a finite set of points is sufficient, it is much more efficient to apply an inverse DFT (using an FFT algorithm), then zero-pad the time-domain data, and apply a DFT (again, using an FFT algorithm). This will give you an equidistantly sampled DTFT with a sample density determined by the DFT length.