I'm brand new to MikroTik, just bought a hAP ac2, it hasn't even arrived yet, but I'm reviewing the RouterOS docs online in preparation.

Figured I'd ask here really quick in case someone already knows the answer. Is there a way to setup the unit strictly as an wireless access point?

I will be connecting this to my existing Router/Firewall, and want to make sure all the wireless clients end up on the same subnet and can see each other on my home network.

Yes, you can. No problem at all.

The lamest way to do it is to use the quick-set menu, select the "Home AP Dual" template, and then in the template:
- configure a static LAN IP address of your router, that is free in your network.
- and remove the check from the DHCP server option.

This way eth1 will still be your WAN interface meaning that after finishing the configuration you have to connect the cable from your LAN to eth2, 3, 4 or 5.

The lamest way to do it is to use the quick-set menu, select the "Home AP Dual" template, and then in the template:
- configure a static LAN IP address of your router, that is free in your network.
- and remove the check from the DHCP server option.

This way eth1 will still be your WAN interface meaning that after finishing the configuration you have to connect the cable from your LAN to eth2, 3, 4 or 5.

"Home AP Dual" in Quickset is not only the lamest way to configure, but also the wrong one - it implies using device as a gateway, with one WAN port and LAN on others + wireless.
The closest Quickset template to what topic starter wants is "WISP AP" with Mode set to "Bridge".
The downside: only one wireless interface is configured automatically, so the other one need to be configured manually afterwards.

However pure WAP is actually a small and easy config, so I suggest writing it from scratch:
1) All ports to one bridge
2) DHCP client (or static address) to that bridge
3) Two wireless interfaces configured
4) Done

Thanks! I got my device today and had it configured in minutes, thanks to you guys.

Quick question though, I'm using the WinBox GUI to connect and configure, which works fine from any device actually connected to the hAP wirelessly.

However I have a hard-wired machine on the same LAN as the hAP (it's not connected directly to the hAP though), and while that machine can see the hAP's IP and MAC, WinBox doesn't seem to want to allow the connection. Is this expected behavior?

Thanks! I got my device today and had it configured in minutes, thanks to you guys.

Quick question though, I'm using the WinBox GUI to connect and configure, which works fine from any device actually connected to the hAP wirelessly.

However I have a hard-wired machine on the same LAN as the hAP (it's not connected directly to the hAP though), and while that machine can see the hAP's IP and MAC, WinBox doesn't seem to want to allow the connection. Is this expected behavior?

No it's not.
If they are in one L2 network, you should be able to connect to it by MAC.
So a thing to check is a list of interfaces, from which you are allowed to connect to a device by MAC:
in GUI:
Tools -> Mac Server -> Winbox Mac Server
then check if your bridge is present in the needed list:
Interfaces -> Interface list
and add it if it is not there.

The MAC WinBox Server interface was initially set to LAN, which explains why I couldn't get there from the wired machine. Changing it to ALL got it working across the board, but I finally decided to allow it only from the WAN.
Thanks for all your help. Looks like I made the right choice with this device, the community here is great!

Uh, wait. You said you wanted to use it as an AP only.
Then you should have no WAN interface at all, it should be just bridging (wifi is LAN, ethernet is LAN)... right?
Or am I missing something?

Uh, wait. You said you wanted to use it as an AP only.
Then you should have no WAN interface at all, it should be just bridging (wifi is LAN, ethernet is LAN)... right?
Or am I missing something?

At this point all real WAN/LAN distinctions are already removed from configuration.
That's just names of two default interface lists.
But I agree: to make the config more readable, it's better to add all ports to "LAN" list and create separate one with self-explaining name (like "windox-mac-allow") serving the only purpose - listing interfaces from which winbox MAC access is allowed.