This activity is one I use often with my students who delete one sound in a /s/ blend word. I present a strip of pictures with minimal paired words and have the student "read" them, reminding them to think about and feel what their tongue and lips are doing to make the sounds in the words.
Included are minimal pairs for /sk, sn, sp, st, sw, sl/. Paired pictures are provided for both the child who omits the /s/ in the blend as well as the child who omits the second sound of the /s/ blend word. 6 - 11 strips are provided for each blend.
Try the "L" version for free here: https://www.teacherspayteachers.com/Product/Minimal-Pairs-Production-Liquids-and-Glides-715448