I use individual sensory bins and have them sit at the kitchen table, prevents anyone walking around and dumping stuff everywhere. I use rice and just fill it 1/3 full, definitely not to the top. Then give them lots of cups, bowls and measuring spoons. They love just dumping it back and forth into the containers. It does make a mess, but you can train them to try and keep it in the sensory bin as best as possible. It can keep them so actively busy that is worth the mess every once and awhile.

As for wasting food, the rice gets used over and over again so I wouldn't really consider it wasteful.

It is really easy to colour the rice too, makes it more visually appealing.

I did this with my 22 month old daughter (as well as the older kids) and she really loved it. Made a huge mess though. But her obvious enjoyment was worth it.