Is there a way to search for all tasks with a reminder for today?
No, not exactly. If the reminders are default reminders, meaning they are 30 minutes before, or the reminder is within the same day of the task, then you can just head to the Today view to see all these tasks.
Though, if your reminder is days, months before the task then there is no way to search for tasks with Reminders at this time. Feel free to add this to our Votebox. http://todoist.com/Vote/