Slice the cucumbers open lengthwise, then place cucumbers flesh side down and smash the cucumber halves with the flat side of a large knife. Cut at an angle into 1-inch pieces and transfer to a large bowl.
Add the avocado chunks, green onions, lime juice, cilantro, jalapeño, pepitas, and salt to the bowl. Gently toss to combine. Taste and add more salt, if necessary. Cover and place in the fridge until ready to serve.