Achhar is combination of salt , pepper and amilo. Skin it, keep the part you think is soft enough to eat.
Boil it then dice it as your have seen back home. Now add all ingredient you could think of and available to you. Use Til for chhop. It will be a trail and error for success.
Bungo ko matra hudaina sathi, You will need usineko aaloo. Peel the Bungo and bahira ko chippyeko falne, kalilo lai usinne, ani aaloo pani usinne. bungo lai katne, aaloo lai musne, ani khorsani, noon, amilo, beshar halera molne...
aaba tel tatayera (methi, jeera, rato khursani) halne, ali ali dadaune ani achar ma halne, ani Til ko chop ni halne, sabai halera molne ani mitho aachar khane...
Let us know how it turns out.
BTW: Nepal ko jasto Bungo (masino kera ko) yaha hudaina so Nepal ko taste chai aaudaina.