python 3:
from ctypes import windll
windowName = 'Adobe Flash Player 10'
width = 2560
height = 1024
menuHeight = 20
GWL_STYLE = -16
WS_CAPTION = 0x00C00000
WS_THICKFRAME = 0x00040000
HWND_TOP = 0
SWP_FRAMECHANGED = 0x0020
hwnd = windll.user32.FindWindowW(None, windowName)
ws = windll.user32.GetWindowLongW(hwnd, GWL_STYLE) & ~(WS_CAPTION | WS_THICKFRAME)
windll.user32.SetWindowLongW(hwnd, GWL_STYLE, ws)
windll.user32.SetWindowPos(hwnd, HWND_TOP, 0, -menuHeight, width, height+menuHeight, SWP_FRAMECHANGED)