  This paper is devoted to the open problem in $\mathbb{F}_1$-geometry of
developing $K$-theory for $\mathbb{F}_1$-schemes. We provide all necessary
facts from the theory of monoid actions on pointed sets and we introduce
sheaves for $\mathcal{M}_0$-schemes and $\mathbb{F}_1$-schemes in the sense of
Connes and Consani. A wide range of results hopefully lies the background for
further developments of the algebraic geometry over $\mathbb{F}_1$. Special
attention is paid to two aspects particular to $\mathbb{F}_1$-geometry, namely,
normal morphisms and locally projective sheaves, which occur when we adopt
Quillen's Q-construction to a definition of $G$-theory and $K$-theory for
$\mathbb{F}_1$-schemes. A comparison with Waldhausen's
$S_{\bullet}$-construction yields the ring structure of $K$-theory. In
particular, we generalize Deitmar's $K$-theory of monoids and show that
$K_*(\Spec\mathbb{F}_1)$ realizes the stable homotopy of the spheres as a ring
spectrum.
