There was a potluck lunch at Br’s (3 1/2) preschool for the last day of the regular school year. We were supposed to bring “something with fruits or vegetables”, so I asked Br if he wanted to make “his salsa” for his friends at school.
We’d made this once before. Br really enjoyed doing, and we all ate it, even Bl! It is surprisingly good, and is a great way to get Br involved in the kitchen.
Materials:
-Bowl
-Kitchen Shears
-canned “Fire Roasted Tomatoes”
-can opener
-green onions
-herbs (we used fresh oregano & fresh cilantro*)
-lime/lemon (optional)
-tortilla chips (or anything else you like to eat with mild salsa)
*depending on the herbs you use (& the size of the leaves), the parent may want to chop them up first to avoid a “salad” feel
Open the can of fire roasted tomatoes (I let Br turn the handle for the can opener once I had it started). Dump them into the bowl. Arm child with the kitchen shears and have them go at it (with appropriate warnings about sharp scissors and the avoidance of appendage or little brothers)!
I chopped the root end of the green onion off, then passed it to Br to cut up with the kitchen shears. He cut a lot of the pieces really big, so I pointed out to him to cut them smaller with his shears once they were in the bowl.
I had Br pull the leaves of the herbs of their stem. For the oregano, I showed him how to lightly pinch the stem and pull it through his fingers to get all the leaves off at once. He thought that was pretty amusing. 
I chopped the cilantro for him, then had Br use a little scraper to put it in the bowl. I had Br smell the different ingredients, and taste it at different points to “decide what we needed to add”, to help bring in the sensorial component.
We also put in a squeeze of lemon. I squeezed it with my hand, but I probably could have had Br do it if we’d used a citrus juicer or reamer.
Stir, check there aren’t any giant chunks left (and if there are, have them cut them with the shears), and sample!
Post Script: Br had tried to pressure some of his kid friends to try it who apparently weren’t “salsa fans”, but I got a number of compliments from the parents & teachers, & they were shocked to find out Br had made it himself!