Heat a wok with oil (portion for green beans) over medium heat. Add green beans and saute until starting to darken in spots, ~1 minute. Add water and chili garlic sauce and cover with a lid. Steam until beans are tender, ~3 minutes.
Top green beans with lime juice and season with some salt. Set aside and wipe out wok.
Return wok to medium heat. Add oil (portion for shrimp) and then shrimp. Saute until shrimp is cooked through, 4 to 6 minutes. Season with some salt and pepper as the shrimp cooks.
Toast rolls.
Drain liquid off cucumber and carrot pickles.
Spread the inside of rolls with Vietnamese mayo and then fill rolls with pickles, shrimp, and cilantro.
Serve banh mi with green beans on the side. Enjoy!