In a large bowl, combine red onion, serrano chili, garlic, and jalapeño.
In a small bowl, whisk together lime juice and zest, olive oil, vinegar, maple syrup, and soy sauce. Pour over the onion mixture and let the mixture sit for 3-4 minutes.
Add cilantro, mint, chickpeas, white beans, cucumber, and avocado to the bowl.
Season with kosher salt to taste and toss everything together.
Serve immediately or store in the fridge for up to 4 days.
