A tank suitable for a baby leopard frog should be just fine for a tadpole too. You could place them both in that tank.

Crickets are great to start with, they are easy to get, and natural for the frogs. I've found freshly morphed frogs sometimes take their time with starting to eat, so just take it slow and wait till they get started.

Dusting crickets is great, as the little frogs will need all the vitamins they can get. Feeding the crickets fruits and veggies a few days to a week before feeding them to your frogs also helps keep your frogs well nourished. This is called gut loading, you can look up more info on it on this site. It's a new technique for me that I learned from reading things here. There are plenty of other bugs you can feed them, but I am personally waiting till my frog actually starts eating before I start stocking up on a large variety.