Remove space between subplots in Plotly?

Yes there is! You can use specs and vertical_spacing or horizontal_spacing. Here is an example for horizontal_spacing:

from plotly import tools
import plotly.plotly as py
from plotly.graph_objs import *

trace1 = Scatter(
     x=[1, 2, 3],
     y=[4, 5, 6]
)
trace2 = Scatter(
     x=[20, 30, 40],
     y=[50, 60, 70],
)

fig = tools.make_subplots(rows = 1, cols = 2, specs = [[{}, {}]],
                          horizontal_spacing = 0.05)

fig.append_trace(trace1, 1, 1)
fig.append_trace(trace2, 1, 2)

py.iplot(fig, filename="make-subplot-horizontal_spacing")

You can find more tutorials on Plotly subplots page: Plotly subplots tutorial