At your campsite, set up a clean cutting board. Halve the avocados, remove the pits, and score the flesh into cubes inside the skin. Scoop out the cubes into a medium bowl.
Add the halved cherry tomatoes, diced cucumber, red onion, and cilantro (if using) to the bowl.
In a small cup or jar, whisk together the lime juice, olive oil, salt, and pepper. Pour over the salad.
Gently toss everything to combine. Taste and adjust salt or lime as needed. Serve immediately. Store any leftovers in a sealed container in your cooler for up to a few hours — the lime juice helps slow browning.
