Last night we were having Science Time in the kitchen and needed some pepper. When the salt was revealed in the same cabinet it became the highlight of Science Time: dumping it onto a plate, running her hands through it, sprinkling it on the table. I initially imagined just reclaiming her "cereal box" (see last step) and filling it with salt. Then I remembered seeing colored rice previously. I thought it would be fun to try to make colored "sand" out of salt.

Step 1: Supplies

Salt

Food coloring

Hand sanitizer

Step 2: Making Colored Salt

Pour some salt into a bowl. I only used about one to two tablespoons since I was running low, but exact measurements are not necessary for this project.

Then add a few drops of food coloring. I used 4, but how vivid your colors are depends on the type of food coloring you have and the ratio of salt to coloring.

Stir with a fork or spoon until coloring is evenly distributed.

Next add a few drops of alcohol hand sanitizer.

Stir again until evenly distributed.

Consider spreading it out into a thin layer and letting it dry for at least an hour to minimize the color that transfers to kids' hands.

Step 3: Play Time

Time to play! This is what our salt "sand" looked like when all the colors were mixed together.

Step 4: Tips and Alternatives

You can probably use rubbing alcohol or vinegar instead of hand sanitizer since I have seen that for colored rice projects.
I tried making purple, but when I added red and blue I got a greenish color. Then, I tried mixing red and blue food coloring to make purple prior to adding it to the salt and still got a greenish hue for the final mixture.
Her hands initially did not look stained at all, but after 30 minutes of playing with it her hands had turned a little green. If you let it dry for longer it may avoid this issue.
For colored rice I have seen that you can make it in a plastic bag
or a plastic box that you are later going to store it in and shake it instead of stirring.
Natural dyes seem like a good option as well.
Consider making a very large volume of this. Salt is very cheap. We have a large shallow storage box we have been using as a "sand" box that is leftover cereal and pasta. My original idea was to put at least five canisters of salt into it.
Alternatively, you could use white salt as "snow" since it is Christmastime. This would be even easier and no issues with potential food coloring on the kids' hands.