If there are only specific properties that you need to get, you can add them as claims in your ApplicationUser class like the following example:
public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser, int> manager)
{
    // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
    var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
    // Add custom user claims here
    userIdentity.AddClaim(new Claim("FullName", this.FullName));
    // or use the ClaimTypes enumeration
    return userIdentity;
}
This gets wired up from the Startup.Auth class:
    SessionStateSection sessionStateSection = ConfigurationManager.GetSection("system.web/sessionState") as SessionStateSection;
    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
        LoginPath = new PathString("/account/login"),
        CookieName = sessionStateSection.CookieName + "_Application",
        Provider = new CookieAuthenticationProvider
        {
            // Enables the application to validate the security stamp when the user logs in.
            OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, ApplicationUser, int>
                (
                     validateInterval: TimeSpan.FromMinutes(30),
                     regenerateIdentityCallback: (manager, user) => user.GenerateUserIdentityAsync(manager),
                     getUserIdCallback: (id) => (id.GetUserId<int>())
                ) 
        }
    });
Then, you can access the claim (in a view or in a controller):
var claims = ((System.Security.Claims.ClaimsIdentity)User.Identity).Claims;
var claim = claims.SingleOrDefault(m => m.Type == "FullName");
No forms authentication tickets here.
If you want the full user details available, you could always create an extension method like the following:
public static ApplicationUser GetApplicationUser(this System.Security.Principal.IIdentity identity)
{
    if (identity.IsAuthenticated)
    {
        using (var db = new AppContext())
        {
            var userManager = new ApplicationUserManager(new ApplicationUserStore(db));
            return userManager.FindByName(identity.Name);
        }
    }
    else
    {
        return null;
    }        
}
And call it like this:
@User.Identity.GetApplicationUser();
I would recommend caching if you're calling this all this time, however.