Q: How do you insert bullet points in tables in Pages for iOS?

Unfortunately it appears as though you can't.

Try holding down the - (hyphen) key (on the numeric keyboard).

DDD47 is exactly right. Bullet lists (with indentation) can be achieved by pressing and holding onto the hyphen key and selecting the bullet point. This will insert the symbol and add indentation. Upon pressing the return key, it will create the next item in the list.

This also applies for anywhere else in the a Pages document.

In the current version of Pages, 5.6.2, you can type something in the table cell and only then will the customary Bullets & Lists option appear in the Format Inspector under the Text tab on the right.  To make this easier, Pages should be updated to show the Bullets & Lists option immediately when a table cell is clicked.

You do realize you are replying to a thread that is over three years, and several version of Pages, old, right?