Okay. The onion thing. Without bothering to take the skin off the onion, slice off the top. Then take a small slice off the circumference to make a flat surface to rest it on. Now you have free corners from which to peel the skin. Do it.

Lay the onion down flat on the bit you sliced off. Hold it in a claw-like grip near the top of its curvature. Make even parallel cuts, as far apart as the size you want your dice, from the stem end nearly but not completely to the root end, knife blade parallel to the work surface. I prefer to start near the bottom and work up.

Now make even parallel cuts with the knife pointing stem-to-root and perpendicular to the work surface, again, almost but not quite entirely to the root end.

Now start at the stem end and make as if to slice round slices off the onion. These slices will fall apart into lovely diced onion. Yay.

I don't know what principle is behind making the offset better, but I know I can get a lot more precision with it than I can with a conventionally-shaped bread knife or a long knife with a serrated edge. I go with what works.

And your mother knew about the silver scissors because cutting paper DULLS them.